How much did you pay for LW? Is sounds like you've been scammed...there's no lifetime membership. LW basic is free & Pro costs $18.88 for 6 months of updates & email support. The only official site for downloading either version is www.limewire.com
Check the 2 threads below for more info (page 5 of the first thread has a list of scam sites).

http://www.gnutellaforums.com/showthread.php?t=28751

http://www.gnutellaforums.com/showthread.php?t=44499

Depending how long ago you paid, you might still be able to get your $ back. You should call your bank/CC company & report this.

Re 4.12.10...I don't know what site you've downloaded that from but there are no trial versions from the official site, just the latest stable release & a Beta version.