'ddlReason_Level_2' has a SelectedValue which is invalid because it does not exist in the list of items.

I am creating cascading dropdown lists and i receive the "'ddlReason_Level_2' has a SelectedValue which is invalid because it does not exist in the list of items.
Parameter name: value " error when i change appenddatabounditems="false". When its true, it appends ALL of the data items and thats not what i want. I only want the items associated with the value in the first dropdown list. Any tips? p.s. all of the values in the datasets are sound. Something else  is up...

 

<asp:DropDownList ID="ddlReason_For_Contact" runat="server" < ...