紧急求救！关于DBX中的BlocktablRecord的迭代器问题，有代码

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AcDbDatabase Db(Adesk::kFalse);
Acad::ErrorStatus err;
err = Db.readDwgFile((const char*)szProjDbPath,_SH_DENYNO,Adesk::kFalse);
AcDbBlockTable *pBlockTable = NULL ;
err = Db.getSymbolTable(pBlockTable, AcDb::kForRead); AcDbBlockTableRecord *pBlockTableRecord = NULL;
err = pBlockTable->getAt(ACDB_MODEL_SPACE, pBlockTableRecord,
AcDb::kForRead);
pBlockTable->close();
AcDbBlockTableRecordIterator* pIterator = NULL;
err = pBlockTableRecord->newIterator(pIterator,true,false); 为何上述代码在arx工程中执行的不错，而在dbx中就挂了??告诉我是createfailed（最后一句） 请大侠帮个忙拉

sdwtao

ZD