transfer queue will not overwrite files

Hi,
Files that I have scheduled in the trasfer queue will not upload to the ftp server. I have specified that the default action should be to overwrite files but when I check the transfer log there is an entry stating that overwrite wasn't possible. If I manually drag and drop the file to the ftp server, where an overwrite is required, the file is uploaded and replaced. The default action of overwrite is taken. Any suggestions to make scheduling work?

thanks,
Wes

I forgot to include that I'm using SmartFTP v2.0
Please let me know if I can provide any other info.
thanks,
Wes