[求助]關於用TOraQuery控件cursors問題!

請問有知道為什麽執行下面代碼時經常會出現下面一行的錯誤信息的嗎？應該怎麽樣釋放cursors呢?
ORA-01000: maximum open cursors exceeded


with OraQuery2 do
begin
Close;
Sql.Clear;
Sql.Add('SELECT A.MO, A.ISN, A.KPSN, A.KPITEM, A.BIOS,A.PCBA, B.CUSTITEM,B.ITEMNM, B.ITEMSP, C.KPCOUNT FROM MOKP_D A, ITEM B, MOKP C '
+ ' WHERE A.ISN=:ISN AND A.KPITEM=:ITEM AND B.ITEM(+)=A.KPITEM AND C.MO(+)=A.MO AND C.KPITEM(+)=A.KPITEM');
ParamByName('ISN').AsString := isn;
ParamByName('ITEM').AsString := item;
try
Open;
except
on E: exception do
begin
LogToFile2.WriteToLogFile('MOKP_D A, ITEM B, MOKP C: ' + E.Message);
StrList.free;
exit;
end;
end;