I noticed you said you mapped 3 channels is that because you used a .lst file and is that something i should be doing or is that truly optional?
I've been tinkering for the past week and still have no progress on this problem. I'm thinking of waiting for windows 7 media center -- I mean Media Portal is great but without a TV guide its useless for TV. I switched from MythTV .20 (user since .17) to media portal but I've never gotten TV guide to work on any version of Media Portal 0.98 to present. I feel like I'm so close this time but don't know what to do next....
The only issue I heard of with this is that if you have a non-existent channel mapped it stops it working.
I would recommend decreasing the variables and do some sanity checks.
First try mapping only 1 channel. (Pick a standard commonly used channel).
If it fails then reduce your downloaded guide to that 1 channel only and try again.
Remember to hit that save button and then ok or the mapping will be lost.
(my first id10t error was not realizing to hit SAVE and then OK).