This behavior, to me, is consistent with the hypothesis that MyIE2 somehow lost my BBS cookie in the middle of a browsing session, at a point in time between the time I pressed "Reply" and the time I submitted the reply by pressing "Continue". This does not give me a lot of confidence in MyIE2...
Every browser I've used on the BBS (MSIE, Netscape 4, Mozilla, Konqueror) loses the cookie from time to time. I agree it's especially annoying in mid-reply. I don't think it's a client-side problem.

Peter