unexpected char: 'U'. when File.WriteAllBytes()

File.WriteAllBytes(“C:\Users\koneo\Desktop\swagtest.unitypackage”,www.bytes);

So I don’t know what’s wrong, if you wan’t the whole script, here it it:

// UnityScript
@script ExecuteInEditMode()
import System.IO;
class MyWindow extends EditorWindow {

    private var www : WWW;
    var target : Renderer;
    var texture : Texture2D;
    var texture2 : Texture2D;
    var texture3 : Texture2D;
	var one : int = 1;
	var done : boolean;
	var loc : String;
	var lo : String;

    @MenuItem ("Window/My Window")
    static function ShowWindow () {
        EditorWindow.GetWindow (MyWindow);
    }

    function OnGUI () {
        if(GUILayout.Button("Download")){  
        	//LoadTexture("http://download.unity3d.com/webplayer/images/unity-icon-big.jpg"); 
        	LoadTexture("http://205.196.123.154/8tbwv4bmbj5g/49sddaa4vkxadr1/CtoJS.unitypackage");
        }
        texture = EditorGUI.ObjectField(Rect(3,60,200,20),"Add a Texture:",texture,Texture);
        if(texture){
            EditorGUI.DrawPreviewTexture(Rect(25,150,100,100),texture);
        }
        /*if(texture2){
        	EditorGUI.DrawPreviewTexture(Rect(25,252,100,100),texture2);
        }
        if(texture3){
        	EditorGUI.DrawPreviewTexture(Rect(25,353,100,100),texture3);
        }*/
		if(done){
			
			if(GUI.Button(Rect(200,200,200,100),"Export")){
				//loc = EditorUtility.OpenFolderPanel("Select animations folder...", "", "");
				AssetDatabase.ExportPackage("Assets/Materials/Fade.mat", "Exported Test.unitypackage"); 
			}
			//
			
			if(GUI.Button(Rect(200,400,200,100),"copy from")){
				//lo = EditorUtility.OpenFolderPanel("Select animations folder...", "", "MAT");
				lo = EditorUtility.OpenFilePanel("Hi","","png");
			}
			if(GUI.Button(Rect(500,300,50,30),"Start")){
				FileUtil.CopyFileOrDirectoryFollowSymlinks(lo,loc);
			}
			if(GUI.Button(Rect(560,300,50,30),"To")){
				//loc = EditorUtility.OpenFolderPanel("Select animations folder...", "","");
				loc = EditorUtility.OpenFolderPanel("lol","","");
			}
			//
			
			if(GUI.Button(Rect(500,200,200,100),"Create Asset")){
				AssetDatabase.CreateAsset(www.texture, "Assets/MyMaterial.mat");
			}
			
		}
    }
    function OnEnable(){
    //    LoadTexture("http://download.unity3d.com/webplayer/images/unity-icon-big.jpg");
    	done = false; 
    }

    function LoadTexture(url)
    {
        www = new WWW(url);
        #if UNITY_EDITOR
        if (!EditorApplication.isPlaying)
            EditorApplication.update = MyUpdate;
        else
            WaitForDownload();
        #else
        WaitForDownload();
        #endif
    }

    #if UNITY_EDITOR
    function MyUpdate ()
    {
        if (www.isDone)
        {
            EditorApplication.update = null;
           LoadCompleted();
        }
    }
    #endif

    function WaitForDownload(){
        yield www;
        LoadCompleted();
    }

    function LoadCompleted(){
        //texture = www.texture;
        //AssetDatabase.CreateAsset(www.assetBundle,"Assets/swag.unitypackage");
        //Debug.Log("name = "+www.bytes.ToString);
        File.WriteAllBytes("C:\Users\koneo\Desktop\swagtest.unitypackage",www.bytes);
        done = true;
        
    }
}

Hello, You have missed a back slash after C:.…

try this:

File.WriteAllBytes(“C:\Users\koneo\Desktop\swagtest.unitypackage”,www.bytes);

You have to escape the backslashes!. The backslash is the escape character in C# / UnityScript / C++ / …

You need it like this:

"C:\\Users\\koneo\\Desktop\\swagtest.unitypackage"