Problems printing duplexed 11x17 brochures in 8.1

I was recently upgraded to Adobe 8.1 from Adobe 5.0 and have experienced major printing issues since (never had problems on 5.0). We produce brochures which are printed onto 11x17 size paper, duplexed (top-top), folded and stapled. Since the upgrade to 8.1, the pages are not printing top-top, but rather top-bottom (causing every other page to be upside down). I was then downgraded to 7.0 and experienced the same problem. Tried selecting and de-selecting the "collate" option and still no resolution. Please let me know what can be done to correct the problem.