I have a 92 pont. Bonneville SE.The key turns but it wont start.the antitheft light is on, please help?

The anti theft light is on, and so is the restraint light. I had a harmonic balancer and a fan relay put in it. it was starting fine before. The locksmith says its a dealership problem please can anyone help me.figure this out. I dont have 125.00 an hour to pay for a dealership to fix this