I upgraded to the Beta (free version) and checked the one thing that has been giving me fits with prior versions - The outlook plug-in crashes Outlook 2007 whenever outlook is invoked (started) from an external program (like explorer). If outlook is already running when invoked, there is no problem because the plug-in is already loaded. But if outlook must start, the process of trying to load the plug-in causes it to crash.
Try it if you run outlook 2007. In explorer and with outlook NOT running, browse your hard drive and find a file - any file - and right click, select "send to", then "email recipient". Outlook will try to start and create the email message with attachment, but will instead pop an error window indicating Outlook has stopped working.
Disable the Avast plug-in in outlook... it works fine.
Run Outlook before trying to do the "send to", and it works fine.
Note: The first time I tried this after installing 5.1.798 (and rebooting), it worked. But subsequent times it failed. Not sure if it always works OK the first time after a reboot... I'll check.
I'm not sure if this is an outlook issue or an avast issue, but it sure would be nice to get resolved. Its been out there for a year or more.