I'm not sure if there's any problems associated with using 64bit Vista but try different USB ports. I had to do this until mine was recognised although I'm using 32bit Vista. The ports which eventually saw the device were located at the back of the computer.
I just tried 'Googling' your particular problem and it seems that presently there is no support for the iphone under 64bit. Check out this page here: 64bit iphone - Google Search=
Sorry to be the bearer of bad news. Perhaps a friend or relative has a pc using 32bit you could use?
You'd think they would write stuff like this on the box!
Thanks for your help, it seems there is no support so I will take your advise and use my wifes computer, I am regretting useing 64bit , i see no advantages to an avg user like me. Oh well i wont have to upgrade for awhile.