Sounds like perhaps a typo. CB-* notes shouldn't be numbered that high and wouldn't be marked 2004. I'm guessing it's Series 2004A GB-*. If so, the note would have been printed in April 2007.
My catalogue is a little old and doesn't price this note. Considering that it is part of a 2,880,000-note print run, and that it is in Fine condition, I wouldn't place a value of more than USD$25 on it, and I fear I'm being generous at that. My vote: spend it.
Logged
BWJM, F.O.N.A.
Life Member of CPMS, RCNA, ONA, ANA, IBNS, WCS.
President, IBNS Ontario Chapter.
Treasurer, Waterloo Coin Society.
Show Chair, Cambridge Coin Show.
Fellow of the Ontario Numismatic Association.