Same problem. I am on the xp64 operating system, which isn't supported with either their 32 bit itunes, or their 64 bit itunes so that might explain it for me. Still, until today when I reinstalled it the thing worked fairly well(if you could ignore the blatant negligence of Apple not making the iphone compatible with the 64 bit windows systems) today though I can't seem to do anything to help.
The main things that other people have got to work are: right click on the itunes application and quicktime application go to the compatibility tab and uncheck everything. Or uninstall both programs and install in a new folder. Both of these however failed for me...