After making the changes to the web service calls in my application so that HTTP Keep-Alive was disabled, I had one instance (10 hours later) where it crashed. At that particular moment, I didn’t have time to look into it. I fired it up again to see if it would crash later that evening; it didn’t. It then ran successfully for over 48 hours. I made a few more changes to the application and gave it to a friend who was also experiencing the same error on his machine. This ‘fix’ appear to have corrected the untrappable error from occurring on his machine as well. I’d still like to know how changing Keep-Alive could make a difference on some computer and not others. So for the past three plus days, this problem has not resurfaced with HTTP Keep-Alive disabled during the web service calls.