关于insert语句插入错行的问题

有a,b两个表，还有一个a,b的字段对应表，从将a表的字段名存到一个数组中，读取对应字段表，然后利用循环语句，利用insert语句在b表中抓取数据，每次抓取一个字段，为什么会出现错行的问题，该怎么解决，用update，但是我update的where条件不会写啊private void button5_Click(object sender, EventArgs e)
        {
            string strSrc = "Server=LIUKAI-THINK;Integrated security=SSPI;database=CkMonitor";
            using (SqlConnection thisConnection = new SqlConnection(strSrc))
            {
                thisConnection.Open();
                SqlDataAdapter thisAdapter = new SqlDataAdapter("SELECT * FROM SelectedFields", thisConnection);//读取对应关系表
                DataSet thisSet = new DataSet();
                thisAdapter.Fill(thisSet, "SelectedFields");
                DataTable tbl1 = thisSet.Tables[0];
                int rowCount = tbl1.Rows.Count;
                int columnCount = tbl1.Columns.Count;
                string[]OriginalTableName=new string[rowCount];//原始数据库表名
                string[]TargetTableName=new string[rowCount];//目标数据库表名
                for (int i = 0; i < rowCount; i++)
                {
                    OriginalTableName[i]=tbl1.Rows[i][0].ToString();
                    TargetTableName[i]=tbl1.Rows[i][1].ToString();
                }    
                for (int i = 0; i < rowCount; i++)
                {
                    int count=0;
                    for(int j=0;j<columnCount;j++)
                    {
                        if(DBNull.Value!=tbl1.Rows[i][j])
                        {
                            count++;
                        }
                    }
                    //读取目标数据库的字段名并存在一个数组Target里
                    ArrayList Target = new ArrayList();
                    string strField = "SELECT c.name FROM syscolumns AS c inner join sysobjects d on c.id=d.id and d.xtype='U' and d.name<>'dtproperties' where d.name='"+TargetTableName[i]+"'";
                    SqlCommand thisCommandField = thisConnection.CreateCommand();
                    thisCommandField.CommandText =strField;
                    SqlDataReader thisReaderTarget = thisCommandField.ExecuteReader();       
                    while (thisReaderTarget.Read())
                    {
                        Target.Add(thisReaderTarget["name"]);
                    }
                    
                    thisReaderTarget.Close();
                        for (int k = 2; k < count; k++)
                        {
                            string str1 = "INSERT INTO " + TargetTableName[i] + "(" + Target[k - 1] + ") SELECT " + tbl1.Rows[i][k + 1] + " FROM " + OriginalTableName[i]; 
                          SqlCommand command = new SqlCommand(str1, thisConnection);
                          command.ExecuteNonQuery();
                         }
                    
                }
                MessageBox.Show("插入数据成功！");
                Application.Exit();
                           }
        }57 1 NULL NULL NULL NULL
58 2 NULL NULL NULL NULL
59 NULL 2011-01-01 00:00:00.000 NULL NULL NULL
60 NULL 2011-02-02 00:00:00.000 NULL NULL NULL
61 NULL NULL 122 NULL NULL
62 NULL NULL 13 NULL NULL
63 NULL NULL NULL 1221 NULL
64 NULL NULL NULL 13 NULL
65 NULL NULL NULL NULL 11
66 NULL NULL NULL NULL 13