The access code/PIN for my GRE for Dummies book doesn't work. Upon first use at studyandprep.dummies.com, I got a message that said "invalid access code."
I'm sorry about that, Stefani--I'm Tom--I'd be happy to help you with this.
I've created a technical support case for you and will be emailing you shortly. Please, respond to that email with your registration code, and proof of purchase and I should be able to correct the issue.
Tom with Wiley