Equation Based Modeling in structure mechanics

Hi All,
While solving equation based structure mechanics problem i encountered the following error message-

- Undefined value found.
- Detail: Undefined value found in the stiffness matrix.
-There are 2020 equations giving NaN/Inf in the matrix rows for the variable mod1.u at coordinates: (4.68675e-037,0.000125,-7.65404e-021), (7.65404e-021,0,-0.000125), (5.41223e-021,8.83883e-005,-8.83883e-005), (-1.40602e-036,-0.000125,2.29621e-020), (5.41223e-021,-8.83883e-005,-8.83883e-005), ...

-There are 1519 equations giving NaN/Inf in the matrix rows for the variable mod1.v at coordinates: (4.68675e-037,0.000125,-7.65404e-021), (7.65404e-021,0,-0.000125), (5.41223e-021,8.83883e-005,-8.83883e-005), (-1.40602e-036,-0.000125,2.29621e-020), (5.41223e-021,-8.83883e-005,-8.83883e-005), ...

-There are 2020 equations giving NaN/Inf in the matrix rows for the variable mod1.w at coordinates: (4.68675e-037,0.000125,-7.65404e-021), (7.65404e-021,0,-0.000125), (5.41223e-021,8.83883e-005,-8.83883e-005), (-1.40602e-036,-0.000125,2.29621e-020), (5.41223e-021,-8.83883e-005,-8.83883e-005), ...
and similarly for the degrees of freedom, NaN/Inf in the matrix columns.

Can anyone please suggest why this type of error is coming and how to remove it?

Thank You