I had problems with my Schwinteck slide when we first got our FW, a Jayco. When we were trying to get it to go back in I followed the instructions and there are, indeed, screws in the motors that keep them from spinning. In order to get the slide to work, you need to take the screws out and pull the motor up so it no longer engages the system that moves the "toothed" receivers. Then you can move the slide. That wasn't my problem, but it did eventually get fixed. I would assume that, if the screws did break, the break(s) were caused by come kind of binding within the system. Hope your dealer can get it fixed correctly for you.
2012 GMC 2500HD D/A Crewcab
2012 Jayco Eagle SuperLite HT 26.5 RLS
2009 Crestliner Superhawk 1900
2013 Polaris Sportsman 550 EXP
2008 Polaris Sportsman 700 X2