Ok, not sure what exactly changed, but I gave up last night, came back this evening to try again, and it was working to get past that step. So I kept on going with the meter provisioning. PG&E's website now allow you to put in the info, so I did, and the ISY started scanning. But nothing happened in the PG&E window time, so I called their support line. They told me it's not a supported device, and they had no suggested solutions for me. He actually said that it had previously been a recommended device, but was not any longer due to some change. Seemed fishy to me.
Anyway, since then I've upgraded the firmware and cleared the java cache. I changed the Extended PAN ID to 0000, but now I can't get the website to give me another shot at joining.
Any suggestions?
Thanks.
Edit:
Nevermind! The extended PAN ID seems to have done the trick. I managed to find the link to try joining again, and I appear to be paired with my meter at this point. Thanks for the help!