timestep in stationary study?

I am modeling laminar flow at steady-state. Error message:

Undefined variable.
- Variable: timestep
- Geometry: geom1
- Domain: 2
Failed to evaluate expression.
- Expression: nojac((0.5/sqrt(((((comp1.spf.rho^2)/(timestep^2))+(((6*comp1.spf.mu)^2)*emetric2))+((comp1.spf.rho^2)*emetric(comp1.u,comp1.w))))))
Failed to evaluate variable.
- Variable: comp1.spf.tau_m
- Defined as: nojac((0.5/sqrt(((((comp1.spf.rho^2)/(timestep^2))+(((6*comp1.spf.mu)^2)*emetric2))+((comp1.spf.rho^2)*emetric(comp1.u,comp1.w))))))
Failed to evaluate temporary symbolic derivative variable.
- Variable: comp1.spf.streamlinens@VDN${test@30}
- Defined as: (((-comp1.spf.tau_c)*comp1.spf.res_p)-((nojac((comp1.u*comp1.spf.rho))*comp1.spf.tau_m)*comp1.spf.res_u))
Failed to evaluate expression.
- Expression: d((2*comp1.spf.streamlinens*pi*r)*(dvol),{test@30})

It might be related to a very thin domain in the geometry.

br
Lasse