How to debug multithreaded applications

Hi, I'm using eclipse Helios, due to the work, I need to debug a multithreaded application. This application can run and terminate normally but when I switch to debug mode, I will cause exception and terminated with error code. Do anyone know how to debug such application in Eclipse ?
Thank you.

Better to give more info on error you are getting..

May be you can put a breakpoint in the thread run method to stop it..