All of a sudden, without any changes made to the system (that I can think of) I am not getting any program updates unless I run mythfilldatabase from the command prompt. From the prompt, it runs properly and new info is stored in the database.

However, it does not work when run automatically by mythtv. Looking in the logs is confusing, as /var/log/mythtv/mythbackend.log doesn't report any errors...
2006-05-18 15:03:41.076 mythbackend: Running mythfilldatabase
2006-05-18 15:03:41.080 Running mythfilldatabase

but looking at the 'Backend logs' in mythweb...
0 3387 mythfilldatabase 4 0 2006-05-18 15:03:43 mythtv Failed to fetch some program info
1 3386 mythfilldatabase 6 0 2006-05-18 15:03:42 mythtv Listings Download Started
2 3385 mythbackend 7 0 2006-05-18 15:03:41 mythtv Running mythfilldatabase

So, what can I do? Give up and run it as a cron job?

Ive got the same problem, can seem to work it out been running mythfill by hand the last few weeks.

Works fine from the commandline as the mythtv user np, fails otherwise..

I thought It was being called as acron job but can find and reference to it in /etc/cron*

even checked the mythbackend initscript no mythfill here either..

is there a mythfilldatabase conf file, im going to have a look at the options in myth-setup again..

No it doesn't normally run as a cron job. I think mythbackend runs it.

I have mine running as a cron job now, and it works every time, so plainly the problem is with mythbackend.

Did you specify a log file when configuring mythfilldatabase in the mythtv setup menus. If you did, any errors would be in there rather than the backend log.

Yes I did, but there's nothing in there either, just a few early messages I got when I was setting it up ages ago.
e.g.
Aborting: Config file does not exist: /root/.mythtv/au.xmltv Do you need to run with --configure?
Error in 1:1: unexpected end of file

Like I say, mythfilldatabase itself is fine, just myth's ability to run it is broken. Maybe it isn't even redirecting the errors to this log anymore.