There can be sth in the code during create or destroy of the
component, cause there is no  limitation of use for activex component,
if you didnt implement it. If you use some unknown activex component
in you component one of them can have this limitation implemented and
it can be the problem.

If it doesnt contain other components have a look if it free memory
after closing the form. Maybe there is some object atribute which is
inside uctPartyPC changed and it reaches some value outside the range.
Have a look what is beeing done during initialization and finalization
of uctPartyPC if you have source code. If it is not problem to send me
that ocx, or if you have source, maybe to send me some adjusted
version of this to me, so i try it :) or what is done during
initialization and finalization...