As a side note, I've managed to work around the problems with the HVR-900 after hibernation by using PVR Scheduler. Now my HTCP is very very reliable .
I've updated the TV Card Driver to 3.7.0.1, MP to 0.2.3.0 RC1 SVN 15342 and TVSERVER to 0.3 Beta SVN 15342, so it could be any or a combination of these.