Error: Internal error: cannot convert ElemStruct to int.

Hello,
Today I try to run a new Comsol model,and the same error occurs,
Whenever I try to run the study of the model I get the same error as you.
But there are no errors occur when I run other models.

The following feature has encoutered a problem
- Fearture: Compile Equations: Stationary (sol2/st1)
-Error: Internal error: cannot convert ElemStruct to int.
Internal error: cannot convert ElemStruct to int.
- Value: d7
Error in multiphysics compilation.


I have changed the administor and the computer name. But when I run the model again, the error occurs too.
Could anybody help me with this problem?

Thanks!
Tengfei Zheng