I just downloaded the latest version of PT Stud and none of my previous HH files were imported... but no error were encountered either. I get the: "Starting import, 10 files found..." message, then "Import Finished - 10 file(s) read - 0 new hand(s) were imported" message.
These are stud 8 hands, but I don't think that matters.
Hold on: I was just able to import the UB HHs with the Absolute hand reader. I did a search, but couldn't find any mention of UB in the PT Stud forum... maybe I'm the only one dumb enough to continue playing there