how to get rid of superHolder20000?

[mediaholic]

following:
i wonna create some mc, attach a comboBoxComponent on it,
delete that mc, THEN create that mc again and attach a comboBoxComponent on it again

THE PROBLEM:

by attaching the combo on my x_mc some superHolder20000 mc is created which stoping the x_mc to be deleted!

i tested it with debuger, with breakpoints on each line.
if i dont attach the combo , the mc can be deleted and recreated several times without problems
BUT as soon as u attach the combo the mc can't be deleted NOR the combo can be attached succesfully AGAIN.

so i thoght i'll delete the superHolder20000 before i try to delete the mc, but debuger is showing me that the superHolder20000 is deleted BUT DESPITE OF THAT the mc is not
and everything desapire from the stage.

TRY THIS WITH BREAKPOINTS ON EACH LINE

this.createEmptyMovieClip("x_mc", 123000);
this["x_mc"].attachMovie("FComboBoxSymbol","b",100);
this["superHolder20000"].removeMovieClip();
this["x_mc"].removeMovieClip();
this.createEmptyMovieClip("x_mc", 123000);
this["x_mc"].attachMovie("FComboBoxSymbol","b",100);
x = 1;

oh man, i spend almoust a whole day to isolate the problem,
and i dont know how to solve it

PLEASE CAN ANYBODY EXPLAIN WHY IS THIS HAPPENING?
ANY TUTORIAL ON HOW TO SOLVE THIS?