strange issue in ASP.NET Ajax client side scripting: ASP.NET Ajax client-side framework failed to load

We have faced some strange issue in ASP.NET Ajax client side scripting
The issue details as follows

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)
Timestamp: Tue, 26 Apr 2011 16:18:50 UTC

Message: Invalid character
Line: 1
Char: 1
Code: 0
URI: http://../../ScriptResource.axd?d=JzKN4uR5DgyYaoDORVzMmepU_GKfpwb9ej55-ParCkDVx3npCy73EGC9BE3OxRu-U7yLMB48wpUN2aTLq-tor0k80o1WRlXwc5IGkAxjhe43b2S5p3ADjyTK2Mds85luE3N01A2&t=11e6618b


Message: ASP.NET Ajax client-side framework failed to load.
Line: 49
Char: 34
Code: 0
URI: http://



The beauty of this issue is the website is working properly in some browser without any issue. Even we have tried by IE 8 in one system it was working fine and in the same version of IE8 in the another system it was not working fine. It was bit frustrating us to solve this issue.

There are many posts and suggestion against this issue, unfortunately nothing solved our issue. At last we found one post which helped to solve our issue.
We have fixed this issue by adding following simple line in the Web.Config file

<system.web.extensions>
<scripting>
<scriptResourceHandler enableCompression="false"
enableCaching="true"/>
</scripting>
</system.web.extensions>

The actual problem was in some of the systems IE is not able to decompress the scripts in the client side. This might be they have turned off the “Use HTTP 1.1” option in the advanced setting of IE. If it is turned off the system is behind the proxy server .