Undefined Value Found

I was runing a 2D model and came up with this error..
anyone can help me??


Undefined value found.
- Detail: Undefined value found in the equation residual vector.
.There are 912 degrees of freedom giving NaN/Inf in the vector for the variable mod1.E10
. at coordinates: (-2.83333e-007,-8.5e-007), (-2.91667e-007,-8.5e-007), (-3e-007,-8.41126e-007), (-3e-007,-8.32252e-007), (-2.94182e-007,-8.26412e-007), ...
There are 284 degrees of freedom giving NaN/Inf in the vector for the variable mod1.E20
. at coordinates: (-2.94182e-007,-8.35286e-007), (-2.85849e-007,-8.4416e-007), (-2.62218e-007,-8.43432e-007), (-2.73067e-007,-8.37592e-007), (-2.92567e-007,-8.08802e-007), ...
There are 284 degrees of freedom giving NaN/Inf in the vector for the variable mod1.E21
. at coordinates: (-2.94182e-007,-8.35286e-007), (-2.85849e-007,-8.4416e-007), (-2.62218e-007,-8.43432e-007), (-2.73067e-007,-8.37592e-007), (-2.92567e-007,-8.08802e-007), ...
There are 630 degrees of freedom giving NaN/Inf in the vector for the variable mod1.Ez
. at coordinates: (-3e-007,-8.5e-007), (-2.75e-007,-8.5e-007), (-2.875e-007,-8.5e-007), (-3e-007,-8.36689e-007), (-3e-007,-8.23379e-007), ...