>When I create an OPG (option group) base class, with my own member class (OPT instead of Option), it works find in VFP developer version, but not in the run-time.
>
>The message says "ButtonCount : The specified class library does not exist or does not contain a valid member class"
>
>Any secrets I should know, or is it just impossible. Thanks.

Sounds like you either did not include in your .EXE or SET CLASSLIB to the library with your OPT class in it.