Hi Brian,
There are two issues for the files that you sent. The data type for spatial initial conditions rasters is integer and yours was 64 bit float. In principle this would be ok if you still only had integer values for each cell. However, the no-data value specified for these rasters is -1.797693e+308. Maybe you could change the NO_DATA value to -9999 and try again?
Let me know if that works.
Cheers
Leonardo