You may want to try putting some silicone spray on the lift posts, be careful not to get it on the tent, I always placed a piece of cardboard between the lift post and the tent. Make sure to spray some down between the bushings at the top of each section and lightly wipe off the excess. I did this with ours about 2-3 times a year, it does make it much easier to crank up. Since it's used, this may never have been done.
I hope the cable was tightened up some after the roof was down and latched, if not it is possible a one of the cables slipped off a pulley, but as OnTheGo said it's really hard to say without being there.
2013 Starcraft Travel Star 229TB
2011 Jayco X17Z(traded in)
2010 Jayco Jay Series 1207(traded for the 17Z)
2011 Chevrolet Silverado 2500HD Z71 CC 6.0L/3.73
Reese "Pro Series" 800lb Trunnion WDH w/sway control