have you tried rebooting? ;)

i'd uninstall and reinstall drivers; from my experience usually 2 of the same thing were meant to both run off of one driver, so installing the 2nd time may have screwed things up.

don't use/know about cubase, but in sonar, you have to select the midi devices it recoginizes, and anything new defaults to 'inactive'. you may have to have cubase scan for it / enable it or something.