You will need to edit your global preferences page to remove the word 'money order' from the payment instructions section, before eBay will allow the item to post without errors.
From your Global Preferences page, the field you want to edit is labeled 'Custom Payment Note.'
Technically this field references both checks and money orders, both of which eBay doesn't technically allow, but the error message is referring specifically to money orders.
Be sure to do an 'eBay preview' before trying to submit the item again to verify this error has been resolved.
