do I have to file form 4626 alt min tax - corporation with my form 1120 the IRS says my return is incomplete without this form?

Did you check schedule K box 29c "yes" (you meet the safe harbor test ? if so you are claiming that you qualify for the exemption to filing the form. OPs have also posted that they got a similar notice even though they marked the exempt box. If this is your situation,  call the number on the notice and explain your situation. If you checked "no" or left the question unanswered and are exempt, you could try mailing an amended 1120 along with the notice or you could submit a completed 4626 along with the notice

you could read the form's instructions, 

AFSI = adjusted Financial statement income

FPMG = Foreign Parented Multinational Group

https://www.irs.gov/pub/irs-pdf/i4626.pdf