"Numtets" error in Ephysics?

Anyone knows why this message occurs? I'm using hfss 10 with ephysics, and it occurs even when I repeat one of the hfss example project (antennabowl).

the error message occurs right after solving "static thermal solve" and then could not solve transient part with following message.

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Solve Error Messages:
- Error reading file: NumTets.
- Transient Thermal Solution Process failed
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Please help

thanks