Ive seen this before...did you have some Overrides on the return at one point but you already cleared them?  For some reason the program still remembers those overrides and continues to give this error (sloppy programming).  If youre confident the overrides have been removed, just uncheck the Error checking at Conversion and Efile it, it should go through fine.

To bypass error checking at conversion, you need to EF from the EFCenter, not from within the tax return.   Im at home and dont have Efiling set up here, so I cant give you a screen shot, maybe someone else can help you out if youre not familiar with that screen.