Originally Posted by Uriziel 
I came back to the PC and tried manually removing Alcohol, PowerISO, and VirtualCD in case some drivers had been left behind during uninstall.
I don't no about Tages but other DRM systems have screamed bloody murder if they detected Alcohol or Deamon Tools or similar murky software on the PC.
It might also be a matter of drive incompatibility as Gorath mentioned, either directly (hardware issue) or indirectly (the remnants of your virtual drive tools may still be confusing the OS which in turn screws up the Tages test). However, one would think that if this was the case it would have manifested itself in other instances as well.
Of course a third option could be that the Tages implementation is simply screwed up (it wouldn't be the first time that a DRM system would have to be removed/fixed after launch).
*Edit*
Paraphrased certain areas to due unnecessary confrontational choice of words.