Network Tethering refuses to show USB iPhone Adapter
I'm trying to configure my iPhone 3GS to do network tethering with my MBP. I've tried it on another MBP (10.6.4) and it works like a charm: I turn on tethering on the 3GS, plug in the USB and voilà, a USB iPhone adapter appears in the networking adapter. Super simple.
On my other MBP, I have all the latest patches (10.6.5, latest iTunes, etc.). However, the "USB iPhone" adapter refuses to appear, so the tethering doesn't work.
Why would the USB iPhone adapter refuse to appear? What would prevent my tethering from working?
Thanks!
MacBook Pro, Mac OS X (10.6), French settings