ERROR

    Hello guys,
I'm finishing my degree in electrical engineering (at IFBA)   and I chose to do a final work about CSP (Concentration Solar Power, simulation on SAM). But appears the error above when I did the "parametric analyzis":

"exec fail(trough_physical): C_csp_trough_collector::on(...) COMPONENT defocus failed.
Simulation trough_physical failed :The calculated field design mass flow rate of 5371.26 kg/s is greater than the maximum defined by the max single loop flow rate and number of loops (3036.00 kg/s). The design mass flow rate is reset to the latter.
gen not assigned
Simulation grid failed :gen not assigned
SSC requires input 'gen', but was not found in the SAM UI or from previous simulations
ssc variable does not exist: 'gen'
Simulation utilityrate5 failed :precheck input: variable 'gen' (System power generated) required but not assigned
SSC requires input 'gen', but was not found in the SAM UI or from previous simulations
ssc variable does not exist: 'gen'
Simulation singleowner failed :precheck input: variable 'gen' (Net power to or from the grid) required but not assigned"
How can I solve this?