I guess I really was the only one still using the original program guide and not using the one from mythportal.be
So after replacing my good old mythfilldatabase script with the one as listed there things are back to normal and my database is filled again.
Last mythfilldatabase run started on 2008-10-14 22:01 and ended on 2008-10-14 22:01. mythfilldatabase ran, but did not insert any new data into the Guide. This can indicate a potential problem with the XML file used for the update.
There's guide data until 2008-10-19 19:00 (5 days).
