>>After I login to UT and browse awhile a UT Login Dialog pops up saying my username is not found and asking me to loging. If I login again I can read one or two msgs and the login pops up again.
>
>There's something which makes your cookie to be vanished. Are you using a proxy at the company? Or, any other tools your PC could be faced to which might result in such a situation.

We are using a wingate proxy. Just as mysteriously as it appeared, the problem has disappeared. I had to close the browser a couple of time and log in to UT to get it to stay, but it appears to be behaving normally now.
Thanks for the quick reply!
JLK