"Cannot copy 4: The file exists."

Each night a sceduled batch file executes and copies three
zipped from one Windows 2003 Server to another Windows
2003 Server. Both Servers are current for updates. The
files are renamed by another scheduled job on the
receiving Server. This prevents name conflicts the next
evening.

These jobs ran for several months without problems. About
a week ago one of the zip files failed to copy. The other
two zip have continued without any problem.

I attempted to manually copy the file and received the
error message: "Cannot copy 4: The file exists."

The file does not exist in the receiving folder. I
verified this in Windows Explorer and using DOS commands
at a command prompt. I even issued a Delete command for
the 4.zip file in the receiving directory and received an
error stating that the file does not exist.

I rebooted the source Server and retried. I then rebooted
the receiving Server and retried. All attempts have
failed and the error persists.

Any ideas or suggestions would be appreciated.