sbiddle: Is it a Panasonic unit? If so they record their Blu Ray discs in a whierd format (different to a retail pressed Blu Ray disc) that has compatability issues with many other Blu Ray players out there. I'm guessing that like some other physical players PowerDVD doesn't like it.
My first suggestion would be to try a later version of PowerDVD, 7.x is very old now. Compatability could have been improved in later versions.