A combination of the words uber (the best, ultimate), lag(slowness in a game due to either a bad or overly busy server
) and the suffix z0r (used to add leetness to a word)
The word as a whole means that whatever the word is describing (probably a chatroom or server) is working very slowly. Also sounds cool in front of various nerds and kol occupants (i hope)
The glaz0r part of the word is due to another member of the chatroom where the word was created misreading the part lagz0r as glaz0r and proclaiming his mistake to the room (nerdy snorts and an urbandictionary submission ensues)
Nerd: is it dead in here or uberlagz0red?
Other guy: I just read "uberlagz0red" as "uberglaz0red."
Nerd: lol, uberglaz0red
Nerd: a new word is born!