AS THE CAPT WAS DEPLOYING REVERSERS DRG LNDG, #2 & #3 REVERSERS UNLOCKED & DEPLOYED (GREEN LGT COND), BUT #1 REVERSER WAS BINDING & ONLY MOVED TO THE UNLOCKED PSN (AMBER LGT COND). CAPT WAS NOT WARNED OF THIS COND, THOUGH 2ND OFFICER SHOULD HAVE MONITORED LGTS. CAPT SAID HE RCHD TO CHECK #1 LEVER. AT ABT THAT TIME, ACFT YAWED RGT. DESPITE IMT ACTION BYTHE CAPT, DRCTNL CTL OF ACFT WAS LOST DUE TO YAWING CAUSED BY INOP THRUST REVERSER. ACFT CONTD OFF RWY, CROSSED 2 TWYS &NOSE GEAR COLLAPSED. AFTER STOPPING, EVACUATION WAS ORDERED. EVACUATION SLIDES DEPLOYED NMLY, BUT WITH THE ACFT ON ITS NOSE, USE OF SLIDES AT DOORS 4L & 4R WAS DISCONTINUED DUE TO EXCESSIVE VERTICAL ANGLE OF SLIDES. INV REVEALED THAT AFTERTCHDWN, #1 ENG ACCELERATED WITH FWD THRUST AS #2 & #3 ENGS PROVIDED REVERSE THRUST. AT ABT THE SAME TIME, THE ACFT'S NOSE LIFTED OFF THE RWY TO A 4 DEG ATTITUDE & THE ACFT WENT OFF THE RWY. AN EXAM OF THE THROTTLE QUADRANT REVEALED THE S1-847 SW WAS CURLED/TWISTED & 2 SUPPORT SHAFTS (HOLDING THE SWS) WERE BENT CAUSING INTMT OPN OF THE #1 REVERSER.