Can't sync iPhone with one particular computer

[jbaugh]

Iv'e installed Leopard on all 3 of my computers. I have no problem synchronizing my wife's iPhone to my computer or my daughter's computer (thus ruling out a problem with the iPhone itself as the cause of the problem to be described).
The problem is that I cannot get my wife's PowerBook to work well with her iPhone. When her iPhone is connected, iTunes does not automatically start up. If I start up iTunes there is a long pause and one of several things happens:
1) I get the message "iTunes could not connect to the iPhone because an unknown error occurred (0xE8000001)" or
2) After unplugging and reconnecting the iPhone I may get initial synchronizing to begin. But after copying 2 or 3 music files to the iPhone there is either a never ending beach ball or sometimes the message, "The iPhone'Your iPhone' cannot be synced. The device timed out".

Often iTunes will freeze and only a force quit will escape out of the program.
First I tried to reinstall iTunes. This didn't help. Then I did an Archive and Install. This did not help.
Any ideas? I think the iPhone is not the problem since it syncs well with my other two computers. But my wife really wants to control and sync her iPhone with her own personal computer.
Thanks.
John

[Soulwar]

I have the same problem with my iMac. Does your computer have usb2.0? If not, it will still work, just not easily. First, set the phone in airplane mode. If the phone tries to do anything while syncing it will freeze iTunes. (I.e. Checks for mail, call or text comes thru, etc...) As far as getting it to sync, it's kind of hit or miss. A restart with it plugged in usually works. Also, I've had some luck unplugging the cable from the computer and not from the phone itself seems to do the trick.
I hope this helps...

[Giaguara]

USB 2.0 vs 1.1 could be the problem.
Check if the USB is indeed 2.0, and try quitting iTunes gelper when iPod is not connected.