I have a HCS12 v3.1 system with P&E that used to work fine. Then I took my code and did debugging and integration at a customer site (with another HCS12 and P&E system). Now I brought it back, and the debugger doesn't work any more. It just crashes when you hit F5. Assembly step still works, though. So does another engineer's project, and my code from before I left. And just running (without debugger). An error message that regularly comes up is 'Can't set breakpont at <...address...>' or something like that, if you try to run-to-cursor or set a breakpoint.
Unfortunately, it is simply not practical to gradually roll back what I did on my trip--I changed a lot of stuff, and it would take days.