"Info Worksheet: Business Tax I.D. Number must be entered. Im a sole proprietor and I still input my EIN. Why is a 12 digit Bus Tax ID # required before I can E-file?

It says "Information Worksheet: Business Tax I.D. Number must be entered," but I am a sole proprietor and I still input my EIN. Why is this requiring a 12 digit Business Tax I.D. Number before I can E-file?