Me too, it seems to have been playing up for the last few days:
I can't erase comments, MAKE comments, log out, open chat and one of
two of my friends' profiles won't open either.
I was just about to re-boot/check for connection probs with my ISP
until I saw your message -are you also on Virgin Media?
(just to rule that one out). The tracking cookie is probably just the device
that lets you log in without having to keep re-typing your password/username
so it's unlikely to be that.
Most likely causes of all this trouble IMO:
a) service provider trouble b)internal faults with FB
I'm going to see if it's any different in Explorer now.
MM