noknees: There are to thing that can cause this (or at least these are most obvious to me) I would open the roof from inside and examine the angles. If these are broken it could show up like this. One other thing to check is the clutch in the rear compartment BUT if the roof did work properly earlies I would suspect the angles...
You can find descriptions on how to remove/assemble the roof by using search. Good luck!
'87 MBenz 190E 2,3 8vlv