Network I/O error

for (int Idex = 0; zdIdex < lst.Count; Idex++)

                {

                    string str = lst[Idex];



                    IQueryFilter pfilter = new QueryFilterClass();

                    string aClause = string.Format("zdtybm='{0}'", str);

                    string bClause = string.Format(" and ( lifecycle='{0}'", '0');

                    string cClause = string.Format(" or lifecycle is null)");

                    pfilter.WhereClause = aClause + bClause + cClause;



                 

                    int count = sourceTable.RowCount(pfilter);

                    ICursor pcursor = sourceTable.Search(pfilter, false);

                    if (count > 0)

                    {

                        sdeDatasetList.Clear();                        

                        IRow pfe = pcursor.NextRow(); // 这句出现了错误

                        while (pfe != null)

                        {

                            sdeDatasetList.Add(pfe);

                            pfe = pcursor.NextRow();

                        }

                        load(sdeDatasetList, sourceTable, targetTable, _pWorkppaceMDB);

                    }

                }