After using ours most of the winter we had the same problem. What I did was to extend the awning---look at where the awning meets the roller and you should see a mark where the awning should be, (dirt mark) pull the awning on the track back to that mark. Than when you roll it back up it should snug up tight, ours did.
Jim and Jane
2008 Cardinal 30TS
Trail Air Pin Box, Center Point Suspension
Reese 18K hitch - Garmin 1690 GPS
2008 Chevy 2500HD 4x4 Duramax/Allison, Long Box, Smartair
Nights camped in 2011: 120