If you file a Sch C you have no requirement to have an EIN if you do not have employees or collect sales taxes.
Where you probably made the error is ....
1) in the Business info section you said you had one but failed to enter it ... go back and switch your answer
2) in the 1099-misc entry screens you put the income in without the 1099 form info showing the payers EIN ... if you did this then remove the 1099 entry and enter the income on the next screen instead