Issues Running 7.x and 9.x in parallel

Team,

I am having issues running ARIS 7.2 and 9.7 in parallel on the same computer (Win8, RAM 8G). I am working mainly with 9.x now, doing some conceptual work, however, I do have some data still on 7.x and every time when I start 7.x, the 9.x server loses connection and stopped.

Are both instances related? Bug or feature? Has anybody else similar experience?