Thought I could share how I update my tvguide.xml.
Edit the pref.ini to suite your need. Help is in the ini file
start the epg_updaterV2.exe . It runs as a service and will not show up anywhere. The exe file checks your xml file for existing current date and if not found it will run your application of choise specified in the ini file. I use it with O2grabber.exe -grab and it works like a charm. No need for complicated Schedule task or autorun. Just put the exe in autorun and one doesn't have to worry about not having fresh epg info again.
The app will never try to run your xml grabber if it is already running if u specify the ini file correctly.
If u need more functions in the exe file let me know and I'll add it...
http://hem.passagen.se/lar282/xschedule/
zipfile is called epg_updaterV2.zip
//Lasse