Hi Basil,
I have the exact same issue in the last fortnight and have still not received a resolution. I agree it is a software issue, not ATO - however MYOB have no assistance beyond the message you have screenshot. The ATO advise it's not their issue - the company has been re-registered for PAYG W/H and should be able to lodge through STP2.
My situation has come about due to a company not employing for a number of years. They have now recommenced employing, during which time STP2 was introduced. I'm thinking I'll have to setup another software subscription other than MYOB to test and swap if it works.
We shouldn't have to go to this extent to work around though.
Hopefully someone can provide some advise!
Kind Regards,
Dee