An SR-1 is an endorsement from your Auto Insurer and is required after you have been involved in an accident and been found to have been uninsured at the time of the accident. The SR-1 is proof for the State that you are now in complaince with your financial responsibility requirements. Failure to fie the SR-1 will result in suspension or revocation of your Drivers License.
An SR1P is a California document that is to be filled out after a collision on the road has occurred between you and another party of some sort (i.e. bike, car, pedestrian).
I'm not sure what state you are living in but in CA the state accident reporting form is an SR1. More than likely it is a form number. an SR22 is a liability form insuring the driver has coverage for 3 consecutive years. and an SR1P is specifically for motorcycles.