A place to look as well would be to check your TuneToChannel.sh file in mythtv-setup, per card. For example, if you use a set top box which has a template ID of #43 (this can be viewed by clicking its "Advanced" properties tab in the AV Wizard screen, and a Provider number of 1, for your tv scheduler, would take up the following format under the input section of the card :
/usr/pluto/bin/TuneToChannel.sh 43 1
This tells mythtv to use device #43 (set top box) and Provider 1.
Just a place to look. Here is a good page on TuneToChannel.sh http://wiki.linuxmce.org/index.php/TuneToChannel.sh
But if you really want to start a square 1 there are some useful bits in my wiki about restoring the mythtv database here :http://wiki.linuxmce.org/index.php/Mythtv:RestoreRecordingsAfterUpgrade
Best of luck to you.