"This device cannot be installed in this socket!"

[valky]

Which parts do you want to install? the mo-ship has different weapon slots...2 only for really big guns. And the other hardware should have a slightly different colour than your fighter ship's (e.g. system stuff is deep blue while your fighter are using a slightly brighter colour)
assuming you have already the next ship, you 'd have 3 Turret slots, 2 big gun slots, 3 system slots.