Sorry I can't help you with the panelization but to verify that you have
valid gerber and drill files I suggest you go to:

http://www.graphicode.com/index.cfm?section=download

and download GCPREVUE. It is a shareware (no charge) package for gerber
and drill viewing which has been expanded over the years to include HPGL
and other engineering type files.

Regards,
Mike Miller.