Failed To Gain Read Write and Access To The System Registry
You can read about it here:
That thread also provides a reference to download a test version. AFAIK, the test version fixes this particular issue (I only have x86 PC's).
jv16 (Jouni) is working on a new build (yet to be released for testing) that is supposed to make PT 2009 x64 fully compatible. It is supposed to be released for testing
JMO...