Tree View Control and User Control

[et]

I created a web form, created a treeview, its parent and child nodes and it
works fine.

I re-created the treeview as a user control, dumped the user control into a
new webform page, and now I get the error "the data at the root level is
invalid. Line 1, position 1"

There is nothing different in the form that works, and the user control
that's on another webform.