I\'m using Eclipse 3.3 and Android 1.6. I installed DDMS on my Eclipse and tried to insert breakpoints as in tutorial https://www.ibm.com/developerworks/library/os-ecbug/ . Howe
To add to Amarghosh answer's, check also your JDK version.
There is a bug with JDK6_u14 et u15, which made your breakpoints "invisible" (the program would not stop during a debug session)
Fixed in the latest one JDK6u16.