Try this:
int sbu = Convert.ToInt32(ddl1.SelectedItem.Value);
report=new CrystalReport1();
string conn1 = " ";
SqlConnection conn = new SqlConnection(conn1);
conn.Open();
DataSet Dataset1 = new DataSet();
DataTable Temp = new DataTable("CISTemp");
SqlCommand cmd = new SqlCommand("sp_cis",conn);
cmd.CommandType= CommandType.StoredProcedure ;
cmd.Parameters.Add( new SqlParameter("@hlevelid",sbu));
Temp.Load(cmd);
Dataset1.Add(Temp);
CrystalDecisions.CrystalReports.Engine.ReportDocument myReportDocument;
myReportDocument = new
CrystalDecisions.CrystalReports.Engine.ReportDocument();
myReportDocument.Load(Server.MapPath("CrystalReport1.rpt"));
myReportDocument.SetDataSource(Dataset1);
CrystalReportViewer1.ReportSource = myReportDocument;
CrystalReportViewer1.DataBind();
conn.Close();
Also, is your report designed using the "CISTemp" table name? If not, that could also be part of your problem. Even though you're assigning the Datasource to the report, the report won't work if the table names don't match up.