My web service is writing out a text file to the temp folder, but where is that ?  If the network service account is a system level account, and its the one doing the writing (I think), then there should be a folder under Documents and Settings \ some account ? \ local settings \ temp 

If Im writing to the temp path with path.GetTempPath( ) , where is that going ? 

I think it is going to C:\Windows\Temp. In your case I would use path.GetTempFileName and work with that file you get...