When I start Outlook 2007, I get a message to the effect that Outlook has encountered serious problems with the avast add-in and asks whether I want to disable it. I answered yes.
I found an avast knowledgebase article ("avast! 7.x: MS Outlook can fail to start with an error message"). Even though it's not the exact message I'm getting, the description was very similar to my situation, so I followed the instructions exactly as given. The only difference was that I didn't find a registry subkey that it describes, but I assumed that was because I had disabled the add-in.
I'm still getting the error. Is there a new avast add-in for Outlook available?