the answer is yes
you should have changed things much more slowly
yes thx ) 10 points, maybe I could use the logger?
I would put in some trace statements identifying things like which grid etc you were working with/instantiating, then see what your console output and/or flash log file is saying. That way you're not intruding on the flow in the way you would in the debugger.
Also use try/catch liberally and again put useful info out in trace statements in the catch part... at least while developing - I am aware that some folk don't like it's use as a rule but I have come into this game from a C++ background and don't have a problem with it!