This is a warning (not an error) generated by system.xml.dll, because the treeview web control uses an older version of the XslTransform.Transform method to transform XML into treeview content. The new method in V1.1 also requires an XmlResolver, so that it can resolve external references to DTDs.
This warning generally won't affect you at all in running under 1.1. Under some rare circumstances similar to the above (e.g. if you have external DTD references), your XML may not load into the tree control in 1.1.
Shanku Niyogi
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