Funcation or Store Procedure Has too many arguments

ALTER PROCEDURE InsertData
	(
		@firstName varchar(50),
		@lastName varchar(50),
		@year varchar(50),
		@school varchar(50),
		@city varchar(50),
		@state varchar(50),
		@country varchar(50),
		@e_mail varchar(50),
		@mobile varchar(50)
	)
AS
	/* SET NOCOUNT ON */ 
	DECLARE @Count int
	select @Count = Count(PersonID) from Person WHERE Mobile = @mobile
	
	IF @Count = 0 
		BEGIN
				INSERT INTO Person (FirstName, LastName, Year1,School,City,State,Country,E_mail,Mobile) 
				VALUES 
				(@firstName, @lastName,@year,@school,@city,@state,@country,@e_mail,@mobile)
		END 
		RETURN @Count
	RETURN

public int Insert(Person person)
   {
       SqlConnection conn = new SqlConnection(connStr);
       conn.Open();
       SqlCommand dCmd = new SqlCommand("InsertData", conn);
       dCmd.CommandType = CommandType.StoredProcedure;
       try
       {

          // dCmd.Parameters.AddWithValue("@firstName", person.FirstName);
           dCmd.Parameters.AddWithValue("@firstName", person.FirstName);
           dCmd.Parameters.AddWithValue("@lastName", person.LastName);
           dCmd.Parameters.AddWithValue("@year", person.Year1);
           dCmd.Parameters.AddWithValue("@school", person.School);
           dCmd.Parameters.AddWithValue("@city", person.City);
           dCmd.Parameters.AddWithValue("@state", person.State);
           dCmd.Parameters.AddWithValue("@country", person.Country);
           dCmd.Parameters.AddWithValue("@e_mail", person.E_mail);
           dCmd.Parameters.AddWithValue("@mobile", person.Mobile);

           return dCmd.ExecuteNonQuery();
       }
       catch
       {
           throw;
       }
       finally
       {
           dCmd.Dispose();
           conn.Close();
           conn.Dispose();
       }
   }