Combo/List Box Error when built with Wizard

[Mmccl]

I am having trouble Building a Combo or List Box that will find a record based on a value that I select.

I use the wizard in Access Office XP to build the Box. The values that the box is based on are the Partner ID and Last Name fields. the Combo or List boxt is Unbound.

I set the Parter ID Row width to 0", so it will not display. In the Row Source property I set the select query to sort on ascending last name.

My form also uses a tab sheet with 5 tabs.

When I select a record every thing works fine for a while. but if I select a record, change a tab view, or select a record, edit it, select another and edit - after a few selections I get an ERROR.

ERROR NUMBER - 2147352567 Occured
Update or CancelUpdate without AddNew or Edit

the code of the List or Combo box is:
_____________________________________

Private Sub List494_AfterUpdate()
' Find the record that matches the control.
Dim rs As Object

Set rs = Me.Recordset.Clone
rs.FindFirst "[PartnerID] = " & Str(Nz(Me![List494], 0))
If Not rs.EOF Then Me.Bookmark = rs.Bookmark
End Sub
_____________________________________

When I run debug, the error is on the last line: Me.Bookmark=rs.Bookmark

Any Suggestions would be a big help. I am way behind in this project.

Thanks
Mike