This has been explained before....
The freezing is literally because of an older version of MythTV Player being installed on the media directors...
Remove the pinning for all local packages from /etc/apt/preferences and do apt-get update and apt-get upgrade
To get MythTV's setup back into the menu, for now, go to the web admin, wizard, media directors, computing applications, and check the MythTV application from the menu. save..
I am trying to resolve this issue, and it will be fixed when i can figure out why the database entry isn't automatically being added.
-Thom