For someone who doesn't really know how to use computers, good job on finding all that info about your PC.
Anyway, there are a couple of reasons why LW works perfectly in some computer environments and needs a little more fiddling for others, but the gist is that every comp set up is differen and there can be factors that will hinder LW's functionality.
Blah, blah.

Whatever....

If all else fails you won't get your money back (as per the sayings of the messages you get before paying) so let's try and make this work, shall we?

You say that you've tried changing the firewall port. Does that mean that you've tried to change the port in LW (by opening and going to the options, etc etc)?
If not, try that. Here are some alternate ports, courtesy of the forums' cleaning lady: http://www.gnutellaforums.com/showth...threadid=24523

__________________
iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

"Raise your can of Beer on high
And seal your fate forever
Our best years have passed us by
The Golden Age Of Leather"
-Blue Öyster Cult-