Error Code when i click a Button

[Akchayan]

I have this error as soon as i click a button:
You have entered the expression On click as the setting of the event property. This expression has caused an error: A problem occurred while Microsoft Access was communicating with the OLE server or the AvitveX control.

And this is the code i have:

Private Sub Befehl109_Click()If IsNull(Me!cmbMitarbeiter) Then
            MsgBox "Fülle das Feld Mitarbeiter aus "
         Else
   DoCmd.ApplyFilter , "[IDPersonal] = [Forms]![foLohnabrechnungsKontrolle]![cmbMitarbeiter]"
End Sub

And i dont understand at all why the error occures, can somebody help?

[Akchayan]

I solved it.

[Welshgasman]

I solved it.

So please tell us how. After all these forums are here to help others?