If you receive the myIR error Invalid Header Record, then you have sent the wrong file. Don't panic, all you need to do is sumbit the correct file.
The default file created by Ace Payroll is called EFILEIRD.CSV . There is an option within Ace Payroll to specify the file name, but either way the file always ends in CSV.
If you get an Invalid Header Error, you have sent the wrong file - just find the correct file and resubmit it.