[Delphinus]

It almost sounds as if something is expiring or deleting your cookies automatically.

As far as I know there isn't an option for auto-logging-out based on an idle timeout or something. Or if there is, it will be the same setting for everyone. I'll try poking around in the admin panel to see if there is such a thing.

I don't have that problem myself but I have the "Remember Me" checked so I don't ever login unless I'm coming in from a computer I don't normally use. If the "Remember Me" option isn't working then I suspect something is erasing or expiring cookies on your end. What browser are you using? I don't think a firewall would normally do it but depending on which one you're using, it might have some kind of "internet security" features enabled by default, that could be interfering.