Wrong Type of Argument

I also have call to another procedure without parameter in program

This works, but when i do with parameter it crashes

procedure  spGetCountries (pContinentId in number
  ,cur_countries out t_cursor)
is
begin
  open cur_countries for select Countryid, CountryName  from tblCountries where continentid = pContinentId;
end;

Still same error. 

protected void ddlContinents_SelectedIndexChanged(object sender, EventArgs e)
  {
  if (ddlContinents.SelectedIndex == 0)
  {
  ddlCountries.SelectedIndex = 0;
  ddlCountries.Enabled = false;
  ddlCities.SelectedIndex = 0;
  ddlCities.Enabled = false;
 
  }
  else
 
  {
  ddlCountries.Enabled = true;
  decimal temp = Convert.ToDecimal(ddlContinents.SelectedValue);
  ddlCountries.DataSource =
  GetData("CasCadingDropDownList.spGETCOUNTRIES", "cur_countries",
  new OracleParameter("pContinentId", new OracleDecimal(temp)));
  ddlCountries.DataBind();
  ListItem liCountry = new  ListItem("Select country", "-1");
  ddlCountries.Items.Insert(0, liCountry);
  ddlCities.SelectedIndex = 0;
  ddlCities.Enabled = false;
  }
  }


Then i have
  private DataSet GetData(string spName, string crsName, OracleParameter spParameter)
  {
  string CS = ConfigurationManager.ConnectionStrings["OraAspNetConString"].ConnectionString;
  using (OracleConnection con = new OracleConnection(CS))
  {
  OracleCommand cmd = new OracleCommand(spName, con);
  cmd.CommandType = CommandType.StoredProcedure;
  DataSet ds = new DataSet();
  OracleDataAdapter da = new OracleDataAdapter();

  cmd.Parameters.Add(crsName, OracleDbType.RefCursor).Direction = ParameterDirection.Output;
  if (spParameter != null)
  {
  cmd.Parameters.Add(spParameter).Direction = ParameterDirection.Input;
  }
  da.SelectCommand = cmd;
  da.Fill(ds);  AT THIS LINE OCCURS ERROR
  return (ds);
  }
  }

I Changed
new OracleParameter("pContinentId", Convert.ToInt32(ddlContinents.SelectedValue)))


but still doesn't work, same error

Perhaps error is in

if (spParameter != null)

cmd.Parameters.Add(spParameter).Direction = ParameterDirection.Input;