iPhone-to-iTunes Fail

The May-December relationship between my new iPhone 3G and my G4 cube has quickly and suddenly given up the ghost. Two days after getting the 2.2 software on my phone (which I would have done with my G4 cube, but its 802.1b connection was way too slow to download the software, and I used my 802.1n on my MacBook Pro), my phone showed the graphic that I needed to plug it into iTunes. Le sigh. So I try to connect to the G4 (which has finally downloaded the software by now), and I get:
Well, carp. I go back to my MacBook Pro and restore the phone. At this point, I suspect I should be able to hook it back up to the G4, but no. iPhoto realizes it needs to launch, but iTunes spends most of two minutes showing the beachball and finally pops up the same error. Unfortunately, my MacBook Pro, which is a working machine (many enlistments in lots of source), has a pittance of the music / podcasts / playlists / etc. compared to that of the cube. I’ve finally given up and copied my various applications over to its iTunes installation, and am about to sync using the laptop instead.

Also, is it too much to ask to have the backup remember the text correction data that it's learned? I’ve taught it not to correct certain words and now it appears I get to do it again. :(

Updated (12/3):
After spending a week of trying to get this to work (rebooting the cube, rebooting the iPhone, force quitting the iTunes Helper app, etc.), and finally getting worked up enough to post about it, last night after posting, it finally worked. For some reason, connecting the phone while iTunes was up was causing the error, but connecting the phone first, and then booting iTunes got me to the “You need to put in your phone password” error, and thence to actual connection (again, having to quit iTunes and ensure the phone was connected and unlocked, and then launching iTunes again). Now, after several hours of USB v1 synching, my phone is mostly back. For some strange reason, the AppStore thinks all of the applications are out of date and is now downloading replacements, but whatever.