Hi, I installed this patch last Friday and had the same problem. I had to uninstall it for text to be visible in OWA. Micosoft now have a fix for this and insist your server hosting OWA has IE5.5 sp2. However, I still have problems as it gives an error message stating that the http service is not running, again uninstalling cleared it.
We have decided not to bother as the securtiy aspect to Exchange is minimal.
Hope this helps.
Mike