Sounds like you have the rods installed incorrectly OR the holes in the control horns are too small and are binding the control rod. Did you follow the instructions when you assembled the glider? A visit to the local radio control hobby shop might save you from something expesnsive and disappointment. Also you might want to look to your local R/C club to get some help there. This link here will help you find a club near your location:
http://www.modelaircraft.org/clubsearch.aspx
Cheers,