We were riding thru trails today for about an hour. We stopped somewhere and shut the bike off and then could not get the bike to start back up. I noticed on the dash the oil pressure indicator was on and when we pushed the button to start the ATV it would just sputter and shoot a bunch of oil smelling smog out of the back of the machine. Any ideas on what the problem could be?

what kind of machine? I know some had in issue with the crankcase breather spewing oil into the air box, it sounds like you might have this issue, remove the air box cover and see if it is full of oil. there is an updated part to fix that particular problem. If your oil is low without an external leak it is burning it.