Name changes

We recently switched our FTP service from Unix to Linux(Suse v10). I now 
have one client that tells me the file names are being changed when they 
get to our FTP server.
The following is an example.
1. File is originally named(on outside vendor machine) as  2006-07-25 
issue.tab
2. Through IE, my client opens up our FTP site and drags the file from 
the vendor site to our FTP site. Let's say the current time is 10:47am.
3. As soon as the file gets to our FTP site the name of the file now has 
the current time appended to it, making the name of the file 10:47 
2006-07-25 issue.tab

Can anyone shed some light on what's going on here and how can I stop 
the time from becoming part of the file name?

Thanks,
Richard