Characters Found After End Of SQL Statement

Hi Folks,

Apologies if this has already been covered, but I couldn't find anything...I've got a form in Access that checks a table for a combo boxes values. If the user adds a value to combo box that isn't in the table I want that record to be added to the table. The code that I've written is:

Private Sub cmbClient_NotInList(NewData As String, Response As Integer)

Dim ctl As Control
Dim db As Database
Dim ssql As String


Set ctrl = Me!cmbClient

If MsgBox("This isn't a recognised client. Do you want to add it?", vbOKCancel) = vbOK Then
Response = acDataErrAdded
ctrl.RowSource = ctrl.RowSource & ";" & NewData

ssql = "Insert into tblclient (Client) Values ('" & NewData & "');"
Set db = CurrentDb()
db.Execute (ssql)
Else
Response = acDataErrContinue
ctrl.Undo
End If

End Sub

When I test the code it appears to work, but I get an error message saying that "Characters found after end of SQL statement"

Can anyone shed any light? I can't see anything obviously wrong with the code, but I must be missing something.

Cheers.