failed to evaluate variable

I am having the following while i am trying to compute the radar cross section problem "radar-cross-section-8613" provided in the model library. Each time i try to compute the following error message pops-up. I have attached a screenshot of the problem. I am beginner to comsol and using comsol 4.0. Please response!!!!

Failed to evaluate expression.
- Expression: d((mu0 const*mod1.emw.iomega*(-mod1.emw.Jsx*test(mod1.trelEx)-mod1.emw.Jsy*test(mod1.trelEy)-mod1.emw.Jsz*test(mod1.relEz)))*(dvol),{test@2})
Failed to evaluate variable.
- Variable: mod1.emw.Jsz
- Defined as: (sqrt((((mod1.emw.sigmabnd/(epsilon0 const*mod1.emw.iomega))+mod1.emw.epsilonrbnd)/mod1.emw.murbnd))*(sqrt((epsilon0 const/mu0 const))*mod1.emw.Ez))
Failed to evaluate variable.
- Variable: mod1.emw.Ez
- Geometry: 1
- Boundary: 1 2 7 8 13 14