Last Friday I wrote about the problem [1] of atlasglob.axd on MSDN. Today I did several tests and found out that the Accept-Language is one of the problems there, and that is the reason why not everyone got this JavaScript error.
If your web browser is using en-us (which is the lower-case culture the MSDN web server is using, too) there is no need to add the atlasglob.axd handler to the web page. If this JavaScript include is missing you don't get the error message that appears because of the missing atlasglob.axd handler. This seems to be a web.config configuration error at the MSDN web server, and maybe an old bug in Atlas while comparing culture codes directly (not lower-case).
When setting English-USA as my first language on my German IE7 it will set the Accept-Language to en-US. A case-sensitive check will then fail, I will get the atlasglob.axd include line,...
I talked with Bertrand Le Roy [2] who will check if the current build is ok and comparing cultures correct. He also send a message to the MSDN team to fix this on the MSDN web servers.