Upload Not working

We bought a new server (Windows Server 2008) to host all of our sites.

Site 1 has File Vista and it works fine (upload and download).
Site 2 also has File Vista but can only download no upload. After selecting a file to upload, it looks like the file is being uploaded with progress bar and file size. But when it is done uploading the file is not in the folder. Other than uploading everthing works. There are no errors in the event log.

Both Sites are on the same server.

Thanks

Does anyone have any idea?

I still need help with this, anyone have any idea?

So I finally figured it out.
The Application Pool on for the two sites were different.
Site 1 Managed Pipeline mode was set to Classic
Site 2 Managed Pipeline mode was set to Integrated
So I changed it to Classic and it works.

Moved module reference from old IIS6 "httpmodule" location to new IIS7 "modules" location.  Works now.