Hi Jody,

This changed in version 8.1D. This is the second line of the things 'fixed in version 8.1D' as outlined in the readme or the release notes:

The Salesperson field can now be left blank in documents. This may be desired in the case of credit notes.

Salespersons are required on orders and invoices to calculate commissions and such, but it is no longer an error if the salesperson field is left blank on any of the Order Entry document types.