If you're having problems with File Transfer Plus then first thing to consider is - Are you using ZoneAlarm (Free or Pro) as your Firewall?
I recently switched to Sygate and since then have had no problems with sending files (both via Messenger and also using File Transfer Plus) so it seem's the problem lies within ZoneAlarm (Great for beginners and those that don't do much more than browsing on the web, but has it's faults - I used it for about 6yr's but realised it was time to go for something that gave me a bit more control) and not the program itself.
The only problem now remaining for me is that the person the other end can still only receive files and not send as they're using ZoneAlarm at present. (It does still load Windows Messenger however [msmsgs.exe] for me aswell so i'd guess that still need's some work? )
Now that it finally work's though i've found it to be an excellent program and recommend it highly!
Thank's RicarDog for your work on it!