Marc Batters , Apr 19, 2011; 08:36 p.m.
It's probably a lens with a bad shutter, and the lens may need a new shutter assembly installed.
When installing a lens onto the body, remember the body must be cocked and the lens must be pre-cocked. Also, when swapping from RB to RZ lenses, the shutter speed dial on the RZ camera body must be turned to something other then the RBL setting, (ie...select a shutter speed).
The camera should beep for things like low battery, mirror dropping, or MLU one minute warning, etc...
I believe, based on the price that 110mm lenses still command on the used market, repairing a 110 lens that is in otherwise good condition, is just a little cheaper then buying a used replacement lens. YMMV