i've had that problem with other boards, but not here.

i am using IE and FF latest builds, and I can login and logout via either.

you might want to clear your cache and delete the x5world and x3world cookies, and it should work.

i can log in and out at will on the home page from either the left or upper right bar, without checking remember me, and it works fine.

doesn't work on bimmerfest....