>These happen SOMETIMES when I shift-click on UT links in order to open new windows and then close One? some? All the windows?
>
>I AM NOT RUNNING A PROXY SERVER. The only apparently non-standard feature in my system is that this machine is set for internet connection sharing.
>
>I use a modem to connect, my network consists of this machine, another desktop, and a laptop.
>
>I'm set to accept cookies.
>
>Michel, please fix this. It wreaks havoc; especially when I'm trying to catch up with 4 days away from the UT.

That setting is local. There isn't anything I can't do on this side. What happens is that your cookie is not broadcasted to the other session window opened. You might want to verify that Per-Session cookie is enabled. But, I guess, you already did. Even if I would accept that transaction, I have no mecanism of knowing that it is coming from you as the cookie is sent blank even if it was set in the prior window. Another possible cause of this is maybe the browser cache is corrupted. Clearing it might solve it. At last, I would reinstall the browser. If that doesn't work, I would reinstall the latest version. If that doesn't work, then there is a ghost somewhere.