problems with partition map

My passport for mac shows up. The folders show up. Nothing shows up inside them. Drive info says the data is there. When I try to verify or repair I get the following message:

Verifying partition map ...

Problems were found with partition map which might prevent booting.

Error Some information unavailable during an internal lookup

Verifying and Repairing...

Problems were encountered during repair of the partition map

Error Some information unavailable during an internal lookup