No, don't pedal backwards, that is all.
Due to the lack of a rear-derailleur on the top-run of the chain, when you spin the crank backwards, the chainline angle will try to straighten the chain. So if you're on the big cogs in back, it'll want to pull the chain towards the middle of the stack. Same if you're on the small cogs. This then causes the chain to be on a different cog than what the rear-derailleur's under and the chain will jump off the guide-pulley and jam.
Again, don't pedal backwards, it's a waste of energy and doesn't do anything for propelling you forwards.