I am having a similar problem, using different hardware. It needs to be reclassified as grave since there is a strong chance of data loss.
My rt73 devices (Edimax EW7318USG) were working fine a few months ago on the same machines I am having failures on now. Yesterday I tried to use one on an amd64 machine and experienced severe OS failure (keyboard locked; can't reboot ; etc.) Today I replicated the failure on an x86 machine, and on that machine the keyboard didn't lock, but I still couldn't reboot as it froze during the shutdown process. More info to follow.