I'm having a similar problem and I wonder if it isn't disk related -- I've suspected problems with the disk with other applications.

Running LimeWire 2.7.3 on a G4/400MHz with 512MB memory, OS 10.2.1.

Usually, with LimeWire running, I can run other applications including mail and/or browser without difficulty (except that communications are slowed, of course).

Other times, LimeWire so totally dominates the computer that I can't even launch other applications. I get a rotating colored "beach ball" for any operation. Even Forced Quit takes forever to launch and execute.

Executing LimeWire and restarting sometimes helps.