Sometimes, when you just fire up the debugger, but haven't started to run a program, you cannot set breakpoints. The debugger just complains that it cannot find the function. It is because, with a program built with Dynamic libraries, not enough has yet been loaded to enable the debugger to find the place where the breakpoint is to be set. The trick then is to:-
break main run
It knows where the main starts and once execution reaches the main program you should be able to set other breakpoints.