Mytv sometimes hangs

[datfreak]

Hi, first of all , this is the most stable version of MP that Ive ever used- thanks for all the good work

Just a quick Q.
Im running RC1 on singleseat using mysql 5 (i could not get the microsoft one to work) and sometimes it hangs to blue screen as I select MYTV from the root menu.
I can end it in task manager- and tv server does seem affected, as it as still recording tv and doesnt miss a beat.
the error log says:
2008-05-21 19:55:26.734375 [ERROR][MPMain]: ProcessWindows exceptionystem.NullReferenceException: Object reference not set to an instance of an object.
at TvPlugin.TVHome.UpdateProgressPercentageBar()
at TvPlugin.TvGuideBase.Process()
at MediaPortal.GUI.Library.GUIWindowManager.ProcessWi ndows()
2008-05-21 19:55:27.750000 [ERROR][MPMain]: ProcessWindows exceptionystem.NullReferenceException: Object reference not set to an instance of an object.
at TvPlugin.TVHome.UpdateProgressPercentageBar()
at TvPlugin.TvGuideBase.Process()
at MediaPortal.GUI.Library.GUIWindowManager.ProcessWi ndows()

over and over and over and over.

Whats causing this? thankyou for your help