Help with Gridview update using object datasource

I have a grid view that is using an object datasource. They code for both is posted below.
When i try to do an update I get the following error:

System.Data.SqlClient.SqlException: Must declare the scalar variable "@Description

any idea what this means and what I need to do to fix it?
Here is the objectDatasource code:

 1 <asp:ObjectDataSource ID="IncidentDataSource" runat="server"
2 OldValuesParameterFormatString="original_{0}" SelectMethod="GetIncidents"
3 UpdateMethod="UpdateIncident"
4 ConflictDetection=&qu ...