Minolta c0072 code, hopper or toner?

My machine keeps shutting off, with this code, and I have to restart by opening the front panel. I know it has something to do with the toner or sub-hopper. I'm very handy at fixing thing, but not a tech. I don't exactly know how to pull this out and clean it, or is it something worse. Its just a machine for our non-profit and not worth a big bill to fix. The machine was a donation. I just installed a new toner bottle a few weeks ago and it ran fine hundreds of copies afterwards.