Windows 7 Pro 'create' Access To Server

I am a database programmer. I publish a client-server application. I have a client who is adding Win7 Pro workstations to their existing network, which at the present time consists of WinXP workstations talking to a Windows Server 2008 R2.The application needs to be able to create and destroy temporary files on the server. The XP workstations have no problem doing this, so the server permissions are set correctly. However, the Win7 workstation is unable to create the files as needed. The same user and folders are being used, so the only difference is the workstation OS.The folders are visible and can be accessed; the application runs, and can read and write existing files on the server, it just can't create/destroy files there.I am not able to recreate the problem here, but I do not have anywhere near as sophisticated a network so I can't truly reproduce their environment.