I have been working and debugging with NetBeans since almost a year with 0 problems. I even updated months ago my PHP version to 5.3.6 and Xdebug to v2.1.0 and worked fine.
Suddenly, NetBeans (6.9.1) is not stopping at breakpoints and I don't remember to have modified any configuration in php.ini or related stuff. The NetBeans option to "stop at first line" works and "xdebug_break();" works, too. Therefore I deduce Xdebug is correctly configured. I have tried in 3 different projects and it's unable to stop. The checkbox in the project properties "Copy files from sources folder to another location" is unchecked, so I don't think it is unable to locate the files.
My development machine is a Windows 7 64 bits Pro. Any suggestion about where I must look will be appreciated.