I am pretty sure you will need to replace folders from windows and not romraider program itself. If I recall correctly you will "point" romraider to where to find the definitions, but editing/updating the definitions folders themselves you will do in windows through explorer. This is done by deleting the subaru folder and replacing it with the new defs. BTW I am running windows 7 with no problems...and I was born in the 60's
Also have you installed ecuflash too? It has the drivers need for the tactrix cable.