Simulation error: Fail to evaluate variable

Hello,

I have a problem running my simulation. The error shows Failed to evaluate variable. - Variable: comp1.mef.I0_1 Does anyone know how to solve it and what is the variable?

Attached please find my simulation model.

The entire error information is: Source selection not meshed. - Geometry: geom1 - Boundary: 8 - Operator: comp1.mef.mi1.term1.int Failed to evaluate expression. - Expression: comp1.mef.mi1.term1.int(comp1.mef.I0) Failed to evaluate variable. - Variable: comp1.mef.I0_1 - Defined as: comp1.mef.mi1.term1.int(comp1.mef.I0)/comp1.mef.mi1.term1.int(1) Failed to evaluate expression. - Expression: d(comp1.mef.I0_1test(comp1.mef.mi1.term1.V0_ode),{test@2}) Failed to evaluate Jacobian of expression. - Expression: comp1.mef.I0_1test(comp1.mef.mi1.term1.V0_ode)

Thanks!