As regards the error arising from the missing Retired Date column add the column back to the table in design view. Having an unused column in the table won't do any harm, but hopefully should avoid the error arising again.
For the error with the embedded macro used as the OnClick event property of the txtOpen control, try changing the macro's WhereCondition argument to a fully qualified reference to the ID column:
"[ID] = " & [Forms]![NameOfAssetListFormGoesHere]![ID]
I've assumed here that the ID column is a number data type. If it's a text data type use:
"[ID] = """ & [Forms]![NameOfAssetListFormGoesHere]![ID] & """"
As regards the NotInList event procedure, the following is an example of code for this, which is used to add a new employer. By making the relevant amendments to the table and column names this should work in your present context.
Private Sub cboEmployer_NotInList(NewData As String, Response As Integer)
Dim ctrl As Control
Dim strSQL As String, strMessage As String
Set ctrl = Me.ActiveControl
' subject to user confirmation insert a new row into Employers table,
' inserting NewData value into Employer column
strMessage = "Add " & NewData & " to list?"
strSQL = "INSERT INTO Employers(Employer) VALUES(""" & _
NewData & """)"
If MsgBox(strMessage, vbYesNo + vbQuestion) = vbYes Then
CurrentDb.Execute strSQL, dbFailOnError
Response = acDataErrAdded
Else
Response = acDataErrContinue
ctrl.Undo
End If
End Sub
You'll find other examples of the use of the NotInList event procedure in a variety of contexts in my NotInList.zip demo in my public databases folder at:
https://onedrive.live.com/?cid=44CC60D7FEA42912&id=44CC60D7FEA42912!169
Note that if you are using an earlier version of Access you might find that the colour of some form objects such as buttons shows incorrectly and you will need to amend the form design accordingly.
If you have difficulty opening the link, copy the link (NB, not the link location) and paste it into your browser's address bar.