When i simulate a cam and follower system, I can simulate the motion by simply dragging. However, after i define a motor and a spring , it can run very well although there are two red keys on the lime line. To my disappointment,  it could not work after being some parameters of the motor , meanwhile solidworks shows me a message "

Errors found parsing command. Command ignored.

Errors found parsing command. Command ignored.

Simulation can not continue.

". Even though i changed the parameters i that i have changed back , it still could not be simulated at all . Thanks for your attention!SolidworksMotion Studies