I'm assuming that an infinite recursion inside setRequiresRedraw function happens
like your evntTimertxt has a parent, lets call it sprite1
sprite1 has a parent, lets call it sprite2
sprite2 does not have a parent, but has a mask
and that mask is a child of sprite1
or something like this
so the code
while (parent ...)
parent = parent._parent || parent._maskee;
checks again sprite1, sprite2, mask, sprite1, sprite2, mask, sprite1, sprite2 and so on...
So there might be a problem in your display tree structure.