CAN ANY ONE HELP ME ABOUT VALIDATING A FORM 501 UNDER MVAT

I HAVE FILLED ALL THE RELEVANT INFORMATION AND VALIDATED ANNEXURES SUCCESFULLY

BUT WHEN I AM VALIDATING THE MAIN FORM 501 AN ERROR SHOWS THAT ENTER CST TIN BUT THE DEALER DOES NOT OBTAINED CST TIN AS HE WAS NOT LIABLE UNDER CST.

REPLY SOON !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!