Defendant demands strict proof of legal existence of a party; the capacity of a party to sue; the averment of the execution of a written instrument

The above statements are in the notice of intent to defend letter we got from the defendant's lawyer (insurance co.) in response to our small claims case in the District Court of Maryland for damage to our vehicle. What does it mean? The letter also states: "The Plaintiff's claims are barred by the applicable Statute of Limitations." The date of the accident was in October 2014. The case was filed in November 2014. The defendant "rear ended" our car on a busy street (wet pavement). Defendant now claims we backed into her vehicle. Her insurance refuses to pay for damage to our vehicle (thankfully we had no injuries). There were no witnesses except for 9 year old daughter in our car. What proof do we need?