BCE0051: Operator '/' cannot be used with a left hand side of type 'Object' and a right hand side of type 'int'.

This is PauseMenuScript.js , Im not sure why I got this error

function BeginPage(width,height) {
scaledResolutionWidth = nativeVerticalResolution / Screen.height * Screen.width;
GUILayout.BeginArea(Rect(scaledResolutionWidth/2 - (width/2), nativeVerticalResolution/2 - (height/2),width,height));

}

You must always supply the type of variables, either explicitly or by using a value. In this case explicitly, since the variables are declared inside a function definition.

function BeginPage(width,height) { // wrong

function BeginPage(width : int, height : int) { // right

In line 3 just convert it to a float and then devide it