I know that it's something simple (yet, still alludes me despite my efforts and web-crawling), but what am I doing to cause a NullReferenceException?

DataSet lvDS = new DataSet();
lvDS = bizobj.sqlfetchDS("select [Client Name] from Accounts");
ProvTab_Client_DropDown.DataSource = lvDS;
ProvTab_Client_DropDown.DataBind();

Thanks,