you're creating start number of textfields, all with the same
instance name. that's problem 1 that needs to be remedied.
give them different instance names (related to the value of
x), give each new_mc some way to retrieve that value or store a
reference to the corresponding textfield in a property of the
movieclip so it can be reference after your for-loop completes,
like onRollOver. that's problem 2.