My dh bought me a Rebel XTi (2 days ago) with an extra zoom lens.. but I keep getting the error 99 msg..

so.. i'm not really impressed. I wanted the Nikon D80 originally, but it is quite a bit more, however I think it's worth it to save my pennies and get my 'dream' camera...
What does everyone else think? I haven't even been able to take one picture with my XTi so that's turned me off.. I know I could very well exchange it and not ever have that problem again.. but from what i've read.. it's not that uncommon..
So.. Nikon D80 or exchange my XTi for another?
Thanks!
eta: Or... should I throw a Nikon D40 in the ring here too? And perhaps get an extra lens to go with it?