Hi Dave - I responded to your email a bit earlier today. In case you don't receive that, and to make sure the answer is here for anybody who stumbles upon the thread:
This kind of HTML tag corruption is the tell-tale sign of a well known but unfortunately wide-spread server configuration problem. Your server administrator needs to update the libxml and php libraries on the server:
Once the libraries are fixed on the server the bracket stripping problem should clear right up! In the event that your server administrators are not willing to fix the problem on their servers, you may be able to work around the problem by installing a special WordPress plugin designed to help with the problem: