This error message can have different causes. I will talk about one of them, that I found reading the ASP.net forums (Bug : Setting ScriptPath). This is the type of error that can drive someone insane.
Using this, the ASP.NET AJAX files will be loaded directly from the file system, in contrast to the default, where they are loaded through an HTTP handler.
This is not only useful for debugging, but may also be necessary in specific scenarios where the HTTP Handler might give you some problems.
Depending on your setup, these files can be usually found at:
C:\Program Files\Microsoft ASP.NET\ASP.NET 2.0 AJAX Extensions\v1.0.61025\MicrosoftAjaxLibrary\System.Web.Extensions\1.0.61025.0\Globalization
It appears that using the release version of the
MicrosoftAjaxTimer.js file can lead to trouble when also using a timer on a page.
The problem is in the
MicrosoftAjaxTimer.js file where aparently the minification didn't go so well and a semicolon (;) was left out.
To fix this, open the file and search for the following string:
There should be a semicolon (;) before the
if. Just add it, save the file and be glad that someone else found this for you (not me, congratulate the original guy in the forums)!