I have same problem: my recordings are messed up and finish 0.5-4 hours later then scheduled. Can't figure out why. I tried using EPG, and setting the recording manually to last 1 hour plus a few minutes for pre and post, but it didn't solve the problem.
mysqlcheck --user=root --pass=MediaPortal --auto-repair MPTVDB
No idea why it went wrong but if checking the database has fixed it I will mark as no-bugDone that. Surprisingly the TV server does not show the length of recording or end time. I wonder why? But the start time is correct.
I also did the database repair and fixed a few problems, thanks jameson_uk for the tip! The recording issue seems to be resolved now.
But there is one other thing I noticed and it started a few days ago - every time the scheduled recording starts, I am getting a pop up message on the screen: "Which user account do you want to use to run this program", exactly like described here: Run As Shortcut Fix But the solution offered in that article did nothelp me. I am using Windows XP.