I can twll you almost for sure that if you can't get Basic to work, then it's very unlikely that you will get Pro to work.

One of the biggest reasons for Limewire even having a Basic version that never expires is so that people get a chance to test out the software for as long as they like before buying Pro. This also gives them the right to say no refunds what-so-ever for Pro. as you already have had all the time in the world to try it before buying.

You should make a detailed post in the connection forum asking for help.

Example here:

http://www.gnutellaforums.com/showthread.php?t=61866

Unfortunately that problem isn't fixed yet to my knowledge, but look at how detailed that first post is. It is definitely not lacking info keeping it from geing fixed.