Ok, thanks to all!! I somehow misunderstood the meaning of that tool, but  InteractiveDebugger sounds thus pretty an unhappy name. I have a real massive bunch of CGI code to investigate and frankly printing\dumping\call-stacking in error_log, or logging through Log::Log4perl still let me miss a real debugging experience. I tried komodo-like EPIC plugin, and I stopped looking at Apache::DB/mod_perl as I was debugging most of the time Registry code instead of my own. Trying to make Apache::DBexperience working better I read of PSGI/Debugger and all the rest and I moved on that. Now I realize it's a some better stack trace improvement but far away from what a real debugging should be. "Real Programmers don't need debuggers, they can read core dumps. Larry Wall" .... ok maybe. I can still use the bicycle to make 2000 miles, but when the others use planes out there some doubts arise