"File Not Found" is one of the most confusing errors that can be caused by a lot of reasons, In my case i have the site is up and running except my custom SharePoint 2007 pages under layout folder.
I developed a custom page which uses WCF REST API classes, and it is working fine on my development VM and once i moved wsp to the staging vm i was getting "File Not Found" and after turn off the customerrors and enable stacktrace in web.config, still i didn't get any details more than the method name that raises the error !!
After spending almost 2 hrs to figure out why some pages in my solution (wsp) is working and other they are not, I found that the pages that throw an error are using
Microsoft.Http.dll and Microsoft.Http.Extensions.dll that doesn't exist on the staging vm. and i remembered that those dlls are registered after you installed WCF REST started Kit.
The problem was missing an assembly and not a file !!!
To deploy those assemblies:
1) WCF assebmlies you can find them on the following path:
C:\Program Files\Microsoft WCF REST\WCF REST Starter Kit Preview 2\Assemblies
2)Copy both dlls:
Microsoft.Http.dll and Microsoft.Http.Extensions.dll
3) Add them to your wsp under GAC folder or drag and drop them to GAC.
Hope this helps.
1) WCF REST API :