Check the command text/query pass into the SqlCommand , which is what it is complaining about, but error doesn't show until you execute the command with ExecuteNonQuery :
// Initializes a new instance of the System.Data.SqlClient.SqlCommand class
// with the text of the query and a System.Data.SqlClient.SqlConnection.
// The text of the query.
// A System.Data.SqlClient.SqlConnection that represents the connection to an
// instance of SQL Server.
public SqlCommand(string cmdText, SqlConnection connection);
public class GrossmontBank
//class variables (global - accessible throughout this class)
//scanner object to be used throughout
private static Scanner input = new Scanner(System.in);