I've taken the elevator to the top and am in the room with the beams in the walls. I know you have to go accross on the right hand side but how do you get on the first beam. I have tried running an jumping from the door level. I have also tried lowering Indy down on the ledge and shimmy over to drop on the ledge accross and down a bit from the first beam. Both of these either end up killing me or tossing me in the water below. Any clues on what I'm doing wrong?

If I'm right, you're in the room with water and several columns and platforms. so here is the way of it:

You’re facing a water chamber with several platforms and columns. SAVE GAME! Stand on the edge, turn around and hang on the edge. Hand walk all the way left and drop. Go to the left and jump to the next ledge. Then another small jump to a ledge. Then a short run/jump to the next ledge. You might say DANGER at that point.

The next platform is quite unsteady and you have to jump over it and hang from the last one. If your difficulty is turned down, and you accidentally land on the bad one, quickly continue to the last platform. Once there, watch out for a spider through the webbed door. Through there, get on the platform and get the key. Return outside to the platform and Quick save. Do a running jump over the bad area, back to the previous good platform, and climb up.

Turn left and do a running jump to the platform between the 2 lamps. Now run/jump, to the thin ledge at the end of the room, to hang. Hand walk all the way to the right and drop. Turn around and stand on the edge. Do a standing jump, up arrow and Alt at same time, to next ledge. Quick save, then face the wall and walk to it. Turn left, then back up and hang from the edge, and drop to lower platform. Go forward and hang from the edge, then drop.

From there, jump across to the corner and draw your whip. Turn left, walk forward and use the whip to swing across the room. Go forward and turn left. Jump up to the edge of the next platform and climb. Do a short run/jump to next platform. Use your whip to swing to next platform. Turn left and climb up. Make a running jump across to next platform.

At the wall, turn left and do a run/jump to next platform and pull up. Turn left, climb up and turn left again. Stand on the edge, and do a standing jump, up arrow and Alt at same time, to next platform. Climb up and jump to edge of next platform, and pull up. Turn to face the wall and push the block. Get a treasure. Now pull the block 2 times. Climb up on its edge and turn around.

Use up arrow and Alt at same time to get to the top of the next block. Do a run/jump to the balcony and pull up. Step forward and the gate will close. Use your key to unlock it. Get the plant, then SAVE GAME! Guards arrive at the end of the room.