Dan,
Sounds like your cartridge interrupter is broken or too short. May be a problem with the lifter as well. When the 92 is cycled the last round inserted should be laying on the lifter and as the lever is dropped downward the lifter should raise the the round to angle toward the chamber. The next round in the magazine should be held there by the cartridge stop or interrupter, which is a metal half hook just below the left feedrail and above the exit of the magazine tube. It presses on the rim of the next round in the magazine and prevents it from exiting.
As the lever is cycled rearward back to the closed position the bolt should pick up the round on the lifter and slide it toward the empty chamber. As it does so and the round is well started in the chamber, the lifter will drop back down to pick up the next cartridge. Just before the bolt closes the cartridge stop should release the next round from the magazine onto the lifter and again stop the next round from exiting the magazine.
Open you action and see it you can see the end of the stop. If you can't see it, its probably broken or missing. If you can see it, it may be too short. Often times a short cartridge stop will cause the next round in the magazine to exit UNDER the lifter and really jam up the works. This usually requires that the gun be partially disasmbld. by removing the tube end cap, magazine spring and follower so that the "trapped" round can be removed.
Any competent gunsmith should be able to fix this problem but he may have to order a new part or two to do so. If the lifter is not operating at all then you may have an additional problem. With the gun empty it should "pop" up with authority when you open the action. Failure to do so may indicate a weak or broken lifter spring. Again, not a insurmountable problem.
I really enjoy my Rossi 92 in 357 Mag. It has become one of my favorite rifles. Mine will feed anything but full wadcutter loads and yours should too, once repaired. So get it fixed and start shooting. You will love it.
Good luck,
Reb