程序已封闭，user 42

程序已关闭，user 42.
程序编译无问题，出现上述错误，得知是指针被重复删除，可我检查了半天，不知哪一句出的问题，求高手告知
{
TBuf<20> number(_L(""));
TBuf<128> callNameBuf;
TBuf<20> firstname(_L(""));
CAknTextQueryDialog* dialog=CAknTextQueryDialog::NewL(number);//声明登陆对话框对象
if (dialog->ExecuteLD(R_LICH_KING_CONTAINER_DATA_QUERY2))
{
   CPbkContactEngine* iContactsDb = CPbkContactEngine::NewL();
   CleanupStack::PushL(iContactsDb);
   CContactIdArray* iMyIdArray = iContactsDb->MatchPhoneNumberL(number, 15);
   CleanupStack::PushL(iMyIdArray);
   callNameBuf.AppendNum(iMyIdArray->Count());
                                                                                     CEikonEnv::InfoWinL(_L("Count of Matches"),callNameBuf);
for (TInt i = 0; i < iMyIdArray->Count(); i++)
     {
          TContactItemId id = (*iMyIdArray)[i];
                                                         
          CPbkContactItem* contact = iContactsDb->ReadContactL(id);
          CleanupStack::PushL(contact);//2
          CAknTextQueryDialog* dialog=CAknTextQueryDialog::NewL(firstname);//声明登陆对话框对象

            if (dialog->ExecuteLD(R_LICH_KING_CONTAINER_DATA_QUERY3))
                 {
                     TPbkContactItemField* field = contact->FindField(EPbkFieldIdFirstName);
                     CleanupStack::PushL(field);//1
                     field->TextStorage()->SetTextL(firstname);
                     iContactsDb->CommitContactL(*contact);
                     CleanupStack::PopAndDestroy(field);
                                                      
                  }
             CleanupStack::PopAndDestroy(contact);
              }

          CleanupStack::PopAndDestroy(iMyIdArray);
          CleanupStack::PopAndDestroy(iContactsDb);
         }
}
[解决办法]
原因知道了，是field属于T类，而清除栈只适用于C类和R类，但之后又出现了系统错误-21，有谁知道如何解决么，-23是因为缺少能力我知道，但是-21用同样的方法好像无法解决呀
[解决办法]
-21的问题是我一个应该用open的地方用了read，结贴