CCL: NICS (Nucleus Independent Chemical Shift) question



Hi,
   In  the NICS calculation of an optimised crystal which contain Iodine atom as substituent, I used  a generated basis set which worked for the same crystal's geometry optimisation. But when I ran the NICS calculation it was showing error "Found a floating point number as input". 
I would be really grateful if someone could point me in a functional direction.

 Sincerely
Deepu George