If you were in an accident on a private lot and you don't have insurance and the other drivers insurance is wanting you to pay for the damages and there was no police report or tickets do you pay?

Depends upon the laws of the state. The insurance company could take you to court, and if you lose it would could also cost you court costs as well as the cost that the insurance company paid taking you to court. The owner of the lot could also press charges for tresspass (criminal tresspass in some states). In most states the only time a police report is made is when there is an injury. I know of one incident where the police waited until uninsured person departed the property and then stopped him on city street for no insurance.