Windows 7 and the Plotter

I recently intorduced our first Windows 7 (professional) workstation to our enterprize, it needs to print to an HP Designjet 1055cm plotter, however when I try to load the drivers from the MFG disk I get an error suggesting that Windows 7 won’t allow me to load NT4 drivers. I’ve tried a fix involving using the CCM to change the system to not use this rule, to no avail. Any suggestion?