Hmm it's annoying. I've had it happen but not with LW. For many people it tends to happen after OS updates. Well ... I guess there's the option of reinstalling the OS updates. This is going to be hit & miss if you're willing:

1. See QuickTime 7.0.4 bug stops LimeWire from opening!

2. Security Update

3. Java update fixer

4. 10.3.9 Combo installer

5. If all else fails, try using the Jum build which is a custom beta version of LW; try the nightly build! No installation necessary!