amesim与matlab联合仿真

联合仿真时出现：Error in 'untitled/S-Function' while executing C MEX S-function 'asd_', (mdlOutputs), at time 0. MATLAB error message:
In AMESim mexfunction: asd_, AMESim fatal error
Unable to open file asd_.data, EXIT.
这是怎么回事呢？