Next hint to the problem:

Some forums were operational, some were not displaying the same 'forum_thread_data file ' error found in CP.cgi rebuild.

I uploaded from the original files [downloaded to pc from mem area]- cgi directory:

Resultes -
The forums that were fuctional are still functional and now some additional forums are operational.

Still many forums produce the same [above] error message.

Little help here - Please -
Or suggestions - Things to try that are not intrusive -from those that are not sure what to do either.

Again as always - Thanks In advance
Peace
RAMY