I'm running MythTV (Subversion Trunk) on a Ubuntu 7.10 box. After the daylight savings time changeover, my mythtv box had the correct time, but the Program Guide data was still off by an hour.  Manually running a mythfilldatabase didn't fix it. After checking to make sure that my timezone xmltv settings were set to Auto, I decided to manually erase all of the program data from the database.

(After using mysql to connect to the database, I issued the "delete from program;" command to delete all of the program entries.)

Then I re-ran mythfilldatabase and everything was fixed. (I still don't understand why this didn't automatically fix itself when the ubuntu box changed it's timezone, as all of the program data is supposed to be stored under UTC…)