TreeList SetValue

Hi,
I create a TreeList with custom nodes, storded in an datatable:

DataRow r = treeListNode.dtRoot.NewRow();
                        r["dcObjName"] = item["Name"];
                        r["dcID"] = item["ID"];
                        r["dcObjID"] = item["ID"];
                        r["dcRelID"] = item["relID"];
                        r["dcColor"] = item["Color"];
                        r["dcStatus"] = 1;
                        r["dcFormat"] = item["Format"];
                        r["dcWMIQuery"] = item["WMIQuery"];
                        treeListNode.dtRoot.Rows.Add®;
Everything is fine, until I try to set a value of a specific node with:

foreach (DevExpress.XtraTreeList.Nodes.TreeListNode item in Node.Nodes)
                {
                    pInsertObject.Fill(DSet.pInsertObjcectTable, int.Parse(item["dcObjID"].ToString()), int.Parse(item.ParentNode["dcID"].ToString()), item["dcValue"].ToString(), 1, System.Environment.UserName);
                    ID=int.Parse(DSet.pInsertObjcectTable[0][0].ToString());
                    item["dcID"]= ID;
                    if (item.HasChildren)
                        SaveNeuenNode(item);
                }

After change the value of the node, the whole treelist.nodes is null.
Pls help
Thx
Gregory