THE CHANGES YOU REQUESTED TO THE TABLE WERE NOT SUCCESSFUL B/C THEY WOULD CREATE DUPLICATE VALUES IN THE INDEX, PRIMARY KEY OR RELATIONSHIP.
If this problems occurs within the scheduling system then the problem consist of date formats MPOS uses the USA date format "MM/DD/YYYY" format. If you are a international user you will need to change your date format to the USA format This is done in Windows Control Panel then by selecting - Regional & Languages Settings - Customize, then date format then select Short Date. You can now change the format to "MM/DD/YYYY" then Restart MPOS.
This error may be accompanied by error 444-method not applicable in this context & 3021- No current record.