So after about 5 minutes of sitting there pulling my hair out…..the ajax returned a result and the next part of the process ran.   Sooo….what the hell?!?!  A few days of googling, trying different things, asking other people in the development team, and finally praying (all religions), I came across a blog post that explained that IE6 doesn’t handle closed connections very well.  We had this line in our javascript:

xh.setRequestHeader(“Connection”, “close”);

We now had to change our code to only include this if the browser was not IE6.  I wasn’t sure what performance hit this would have or what side affects it would have, but we’ve been running this for a few years and haven’t seen any difference with performance or had any problems.  If anyone else has a better understanding of why IE6 behaves like this, please leave me a comment!!