with this code I run on
Kentico 5CMS.TreeEngine.TreeProvider provider = new CMS.TreeEngine.TreeProvider(CMS.CMSHelper.CMSContext.CurrentUser);
CMS.TreeEngine.TreeNode node = new CMS.TreeEngine.TreeNode("KP.BatDongSan", provider);
CMS.TreeEngine.TreeNode parent = provider.SelectSingleNode(CMS.CMSHelper.CMSContext.CurrentSiteName, "/Cong-Đong/Nha-nha-nha-310m2-hem-Mimosa-(Khe-Sanh)", CMSUtils.GetCultureCode().ToString());
if (parent != null)
{
node.SetValue("title", title.Text);
parent.Update();
}
but not running on Kentico 6