Error - 81: Tax Account Linked Account is missing
It is very important to check whether your tax-codes are linked to accounts (a General Ledger Account) in MYOB. To ensure they are, in MYOB go to Lists > Tax-Codes and make sure they are linked.
Further information is available via the MYOB Community site here
Error 236: Company name or last name cannot be blank
This means that you have no supplier card attached to your Invitbox supplier when you did the export. You need to open up that supplier via the Admin Tab> Suppliers; Edit> add a MYOB supplier card