At work, we're using a Windows Server 2008 R2 VM as our build server. At the end of the build process for any of our projects, we copy the packaged deployment files to a folder on the server where they'll be deployed. (This is done in a batch command by a service account.)

For most of our projects, which deploy to a Windows Server 2008 R2 VM, this step goes swimmingly. But for one project, which deploys to a Windows Server 2003 R2 VM which resides in a different domain on our network, the .zip files return "Access is denied" and don't copy, though all of the other files copy correctly.

• Our sysadmins say they haven't prevented this in group policy or by other means.
• If I'm logged in the build server as myself and run the copy in the command window, I can't copy the .zip files over either, so it's not just a matter of the service account's permissions.
• If I log into the 2003 server and then copy from the build server to the 2003 server, using the command window, it works, whether I run as myself or as our service account.
• Only .zip files cause the "Access is denied" problem. Even a (fake) .exe file copies correctly.
• All of our other projects have .zip files, and they copy to their 2008 R2 server correctly.

Is there a way I can get the Windows Server 2003 R2 VM to accept .zip files copied from our build server?