If they're just stripped you might push a dowel rod into the stripped hole and then drill the center of the dowel to fit the screws. If they were never installed into anything solid such as a stud, you might have to relocate the awning brackets to a more suitable location.
Of course, doing that would require moving the awning rail too or the arms won't align properly. Good luck.
By the way, I moved your post out of our FAQ/Website Technical Support/Suggestion Box forum. That area is reserved for technical questions and for questions pertaining to this website. Your post will get more attention in this forum.
'11 GMC Acadia SLT AWD
'11 GMC Sierra 1500 4x4 Extended Cab