Hi all,
first I've got to apologize for not being around during the last couple of days. This was because we were very busy preparing a new build that should eventually solve all the problems discussed on these forums so far.
So here it is - a new (pre-release) build of avast 4.5, with a number of fixes created as an immediate response to the support issues we were seeing (both here on the forum and via conventional support entry points).
How to install the beta (we decided to simplify the installation process as much as possible to enable trying this version out even for people who are not so computer proficient - so please don't hesitate and install it even if you normally don't quite do any beta testing). So, all you have it do is download and run the following program
http://www2.asw.cz/misc/aswbeta.exeand it will take care of the rest.

Here's an (incomplete)
list of fixes in this release:
- attempt to solve the "Million timeout messages" issue (Internet Mail provider)
- attempt to gracefully handle SSL enabled connections (pretending the server is actually not SSL compliant)
- attempt to solve all kinds of "Timeout" problems in the mail scanner
- solved the problem where the Internet Mail provider was not starting automatically, and also where it was "Waiting for a subsystem to start" e.g. when the on-access task was restarted (or edited)
- solved compatibility of the transparent mail scanner with Norton Personal Firewall and Kerio Winroute Firewall (please report other incompatible firewall products asap!)
- attempt to solve intermittent crashes in aswTdi.sys
- during the displaying of the "Network Shield blocked attack" message, the user now has a possibility to easily choose "Don't show this window next time" (
this one has actually been a support nightmare 
.
Please, let us know if it does solve your problems (and especially if it doesn't) - we'd like to release the official version asap.
Thank you.
Vlk