I use Outlook 2000 and I have same problem (the only one so far with avast!) with the port 25 and 110 messages at startup time.
Being not a technical person I cannot understand the explanation given in the avast! help section, neither the one given here to Hedgehug about using a program to find out what port is using what application, and apply then the "cooperation". I installed that program and see no port numbers at all.
Can anyone give me a simple solution to get avast! Home using the ports it needs and my other applications using their's with no interference at all and no related messages?
Suspect applications for the port conflict are BlackICE and Spam Inspector,... for the best of my knowledge.