Mind if I SCREAM first

Six very very similar servers running 2003.
Five do nothing but host SQL databases.
These five - run an app my developers made that:
1) Backup the db's
2) Zip them up
3) FTP the zipped files to server #6

The three week old (newest of the five) servers is having issues. FTP from a CMD prompt worked for two weeks and then quite for five days. This morning it worked.

I spent all day yesterday chatting with the data center techs. They were leaning towards blaming server #6 to be the culprit. (permissions etc) Hopefully today I will be successful when they attempt to answer the questions-> Why do the other 4 servers Not have the same problem.

Related to the issue: the problem server takes 30 minutes to transfer a file that the other server can do in 7 minutes.

Yesterday, they had me download an app called WinMRT which looks like a fancy tracert type app. They thought they detected an issue with a switch where server #6 is located...

Anyone have any thoughts on this? Thanks in advance.