If you have a new Mac, you probably are eligible for the free AppleCare support.

Chances are they'll run you through the basic troubleshooting/maintenace steps

(Safe Boot; Repair Permissions; Run Software Update; Safe Boot; Repair Permissions--until all is updated--and then restart.)

If you call them, tell them that you are using a Java Application, because the QuickTime Update from 6.3 to 6.4 causes problems with Java programs like LimeWire.

Anyway, there are lots of us here willing to help out and wish you luck.

Whether you look here or there for help, the info needed would be the version numbers (See Apple Menu->About This Mac), and the error report. You can find the error report by going to the Utilities folder and double-clicking "Console" Once Console is open, there's a menu to Open Logs--look for limewire.crash.log. It will contain the technical info developers need to track a problem.

So--sorry for the length. Post back withOSX version and what steps you've tried (if any).

Cheers