Blow up problem with nesting application

[novice]

Hi Forum,
I was trying to do nesting in my domain. After successfully running the parent domain model. I created a nested high resolution grid inside the bigger domain. My model is blowing up with NaN values in the first time step of FINE2COARSE.

Here I am attaching the log file of my run. I would be grateful if anybody can point out the possible reasons for the blow up.