re:serious ftp error condition

Since going up to SmartFTP 1.5 Build 988 Released, I have been experiencing a disturbing result from direct file transfers.
What is happening is I am getting transfer timeout and 'broken pipe' messages when attempting to direct transfer files of any fair size, like around 18mb. Smaller sized files are fine. The larger sized files do not transfer completely.
Following is an example excerpt from my log file:
Opening data connection to 132.170.10.14 Port: 40581
RETR td1lmail.txt
150 ASCII data connection for td1lmail.txt (132.170.10.14,1447) (18926054 bytes).
Transfer Timeout (20s). Closing data connection.
4105652 bytes transferred. (189 KB/s) (00:00:21)
550 td1lmail.txt: Broken pipe.
Transfer failed.
Log closed


Could someone help me with this? Considering this never happened before the update, I can only assume there is added functionality and I need to adjust my settings, or consider it a bug.

Thanks.