Back in 2004/5, buying Pro entitled you to free updates for 6 months after purchase. So your Pro's well & truly out of date. Sorry, but you'd need to buy Pro again if you want to download a Pro installer. Unless you have your Pro installer saved, installing a basic version would mean that you'd lose your Pro completely

If you originally bought Pro from a scam site offering some 'lifetime membership' then your email address would never have been in the official database.
Membership? - **BEWARE** - Download p2p Clients ONLY Thru Official Sites (click on link)

Is this the connection problems sticky that you've been looking at? If LW 4 Will Not Connect

Did you replace the gnutella.net file? Were there any fixes that you had trouble with? We need your system details