When I build my game to test, why does the menu lose all functionality besides 'exit'?

I built my game to do a quick test, but it loses all functionality besides exit. I cannot start it.

This is my script:

var levelToLoad : String;
var soundhover : AudioClip;
var beep : AudioClip;
var QuitButton : boolean = false;

function OnMouseEnter(){
audio.PlayOneShot(soundhover);
}

function OnMouseUp(){
audio.PlayOneShot(beep);
yield new WaitForSeconds(0.35);
if(QuitButton){
Application.Quit();
}
else{
Application.LoadLevel(levelToLoad);
}
}
@script RequireComponent(AudioSource)

My Start Game is supposed to leave the menu to the prologue, and my about button, to an about page.

In my output_log, I get this.

Initialize engine version: 4.3.4f1 (e444f76e01cd)
GfxDevice: creating device client; threaded=1
Direct3D:
    Version:  Direct3D 9.0c [igdumdim32.dll 10.18.10.3412]
    Renderer: Intel(R) HD Graphics
    Vendor:   Intel
    VRAM:     912 MB (via DXGI)
    Caps:     Shader=30 DepthRT=1 NativeDepth=1 NativeShadow=1 DF16=1 INTZ=1 RAWZ=0 NULL=1 RESZ=1 SlowINTZ=0
Begin MonoManager ReloadAssembly
- Completed reload, in  1.130 seconds
desktop: 1366x768 60Hz; virtual: 3286x1080 at 0,0
 Initializing input.

 Input initialized.

Platform assembly: C:\Users	revo_000\Desktop\ConquestTest1_Data\Managed\System.Core.dll (this message is harmless)
Platform assembly: C:\Users	revo_000\Desktop\ConquestTest1_Data\Managed\Boo.Lang.dll (this message is harmless)
The variables of the 'InvPauseGame' script on 'Inventory' has not been assigned.
 
(Filename: C:/BuildAgent/work/d3d49558e4d408f4/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 53)

Platform assembly: C:\Users	revo_000\Desktop\ConquestTest1_Data\Managed\UnityScript.Lang.dll (this message is harmless)
NullReferenceException: Object reference not set to an instance of an object
  at Hover Script.OnMouseEnter () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script.OnMouseEnter () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script.OnMouseEnter () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script.OnMouseEnter () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script.OnMouseEnter () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script.OnMouseEnter () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script.OnMouseEnter () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script.OnMouseEnter () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script.OnMouseEnter () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script.OnMouseEnter () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at Hover Script+$OnMouseUp$71+$.MoveNext () [0x00000] in :0 
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UnityEngine.HitInfo:SendMessage(String)
UnityEngine.SendMouseEvents:SendEvents(Int32, HitInfo)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)
 
(Filename:  Line: -1)

If anyone could help, that would be great, thanks.

I think that i see your problem, what you need to do is change line 17 to this:

Application.LoadLevel(""+levelToLoad);

Hope this helps!

Looks like your issue may have something to do with you trying to play audio.