it should work, i wouldnt ever do it on the phone
ADB does work on windows 7 x64, ive done it and explained it many times
when debugging is enabled connect the device and open device manager on windows 7. manually update device driver and select from list, select have disk, select location of x64 driver in the android 1.5 r3 sdk, select ADB testing interface.
adb then works
you will have to do it in recovery unless you have a proper rooted kernal like galaxo.