Limewire Problems HELP!!!!

Hey, I recently picked up a MacBook with Leopard (OSX 10.5) and installed LimeWire almost immediately, and everything worked swimmingly. However, just two weeks later, when I tried to open LimeWire, it went to the "would you like to upgrade to pro" screen, and when I hit later, it went to the "tip of the week" popup. When I attempted to close this window to begin using Limewire, my computer froze for a few seconds, then Limewire closed and "would you like to send an error report" popped up. This problem has continued for two weeks now, and I have tried throwing out Limewire and downloading it again, but when i do so, the problem still remains. Any ideas???