[AccessD] Error 2468 - You can't carry out this action at the present time.

Dear List:

I am getting the following error message on a bound form:        

Error 2468 - You can't carry out this action at the present time.

This form has a sub form linked to the main form by the main form's primary key.  (Main form is P.O. Header, subform is P.O. Detail).

I get this error if I try to delete two records in a row.

    DoCmd.SetWarnings False
    DoCmd.DoMenuItem acFormBar, acEditMenu, 8, , acMenuVer70
    DoCmd.DoMenuItem acFormBar, acEditMenu, 6, , acMenuVer70
    DoCmd.SetWarnings True

I also get this error after I try to add a record.  The problem started because I wanted to get the last PO in the file, add one to the PO number, and put the prefix and the new PO number ito the new record:

    DoCmd.GoToRecord , , acNewRec
    
    'If rstPOHeader.RecordCount <> 0 Then
    '    rstPOHeader.MoveLast
    '    Me.fldPOPrefix = Nz(rstPOHeader!fldPOPrefix)
    '    If IsNumeric(rstPOHeader!fldPONumber) Then
    '        Me.fldPONumber = rstPOHeader!fldPONumber + 1
    '        fldPOOrderDate.SetFocus
    '    Else
    '        Me.fldPONumber.SetFocus
    '    End If
    'End If
    'If Nz(Me.fldPOPrefix) = "" And Nz(rstPOHeader!fldPOPrefix) = "" Then _
        Me.fldPOPrefix.SetFocus

Right now the code is commented out.  If I uncomment the two lines:

    '    rstPOHeader.MoveLast
    '    Me.fldPOPrefix = Nz(rstPOHeader!fldPOPrefix)

I get the error when I try to save:

    DoCmd.DoMenuItem acFormBar, acRecordsMenu, acSaveRecord, , acMenuVer70

I checked the web and there is nothing.  Has anyone encountered this before?

Thanks and regards,

Rocky Smolin
Beach Access Software