Hello all,
I had not yet encountered that one before. It can occur on the DragDrop event when implementing drag-drop within a treeview. I have been using drag-drop within a treeview for years and have not had this error reported, but recently a user encountered this. From what I gather, it has something to do with attempting to move a node such that an invalid parent/child relationship would be created, and my code has always guarded against this. I cannot reproduce the user's error.

Has anyone ever run into this before? A quick fix would be to trap for that error, and the DragDrop event would simply gracefully deny the move, but I was hoping for more insight on the cause.

I was not able to find much on a web search of the issue. There is some code in this article which shows the trapping of this error, but in my case, I can't see how the conditions would be right for this to occur. (BTW, this article shows how to use a TV within in Access app, and uses OLEDragDrop, whereas I have a standard VB6 app with "plain" (not OLE) DrapDrop).

Any further insight would be appreciated.

http://support.microsoft.com/?id=209898