I downloaded the new "important security update" as soon as ZA warned me to do so. I then installed it. My email software immediately lost its ability to communicate with my ISP's server. I checked the Zone Labs forums and discovered other users were having a host of problems with this update, and some of them were even having exactly the same issue as me. I uninstalled ZA, and re-installed the previous version. This immediately fixed my email problem. So my advice is to skip this update, and wait for the next one.
No probs here either - CQG, Tradestation, IB, Outllook, Firefox, Spysweeper, Viruscan Enterprise. Did you install it by doing a "Clean Install"? This wipes your previous settings, but is recommended by ZL. ZoneAlarm is a great product - but I would also recommend a Hardware Firewall - so cheap these days (or an old Linux box to do that job).
Look at their message board. Lots of people (including me) had lots of trouble with it. Even the "fixed" updated seems to have problems, too. Very disappointing - ZL products were solid and stable for a long time.