It seems that when adding references to other tables enter those first, then the table that's going to be in the maintenance form last. This sequence worked without any problems.

'''

''' Constructor
'''

'''
Public Sub New()

'Set up to store reference to business object
Private oDept As Dept_acct
Private oUsers As Pur_user

'Instantiate and register business objects
Me.oDept = CType(Me.RegisterPrimaryBizObj(New Dept_acct), Dept_acct)
Me.oUsers = CType(Me.RegisterPrimaryBizObj(New Pur_user), Pur_user)

' This call is required by the Windows Form Designer.
InitializeComponent()

'Get all department records
Me.oDept.GetAllReqs()

'Get all users into grid
Me.oUsers.GetAllUsersSP()

'Register the Users DataGrid as the Navigation control
Me.NavControl = Me.grdUsers

End Sub

I would have thought there shouldn't be a difference, but there was.

CU