fastreport的打印方案以流的方式向表中保存时提示：“操作数类型冲突:text与image不兼容”

大家给看看是怎么回理啊？
procedure Tfrm_fr_design_save.frDesignerSaveReport(Report: TfrReport;
  var ReportName: String; SaveAs: Boolean; var Saved: Boolean);
var
  tempStream : TMemoryStream;
  fangan: TBlobField;
begin
  tempStream:=TMemoryStream.Create;
  tempStream.Clear;
  Report.SaveToStream(tempStream);
  fanganid:=trim(LEdit_fanganid.Text);
  fanganname:=trim(LEdit_fanganname.Text);
  fangandes:=trim(LEdit_fangandes.Text);
  fangancate:=trim(LEdit_fangancate.Text);
  moditime:=vartostr(now);  DM_main.server_connect(rdset_FrSav);
  rdset_FrSav.Remoteclose;
  rdset_FrSav.RTSQL.Clear;
  if (fr_save_lx='open') then
  begin     //修改报表
    try
      with rdset_FrSav do
      begin
        RTSQL.Text:='update sys_rpt set fangan=:fangan '+
                    'where fanganid=:fanganid and dataid=:dataid ';
        RTParams.ParamByName('fangan').LoadFromStream(tempStream,ftBlob);
        RTParams.ParamByName('fanganid').AsString:=fanganid;
        RTParams.ParamByName('dataid').AsString:='DJRPT_'+vartostr(djlxbs);
      end;
    finally
      tempStream.Free;
    end;
  end ;