I have a webapplication running on framework 3.5 and is installed on multiple clients, working perfectly.

Except this one client... where all webservices that the application provide fail with the following error message:

> 
> Compilation Error Description: An error occurred during the
>  compilation of a resource required to service this request. Please
>  review the following specific error details and modify your source
>  code appropriately. 
> 
> 
> Compiler Error Message: CS0103: The name 'Encoding' does not exist in
>  the current context
> 
> 
> Source Error:
> 
> 
> Line 100: string EscapedFileName { Line 101: get { Line
>  102: return HttpUtility.UrlEncode(FileName, Encoding.UTF8);
>  Line 103: } Line 104: } 
> 
> 
> Source File:
>  c:\Windows\Microsoft.NET\Framework\v2.0.50727\CONFIG\DefaultWsdlHelpGenerator.aspx
>  Line: 102
> 
> 
> 

Google points me toward the application might be targeting the client version of the framework or the system missing the system.web dll.

I've checked that both this possibilities are not the cause... Any ideas?