Thread:Extension talk:ConfirmUsersEmail/Another Error/reply (2)

Comparing this to a similar problem in the User Rights List extension, to fix this I'd say in ConfirmUsersEmail.page.php perform the following changes:
 * Change all occurrences of "wfElement" to "Xml::Element"
 * Change all occurrences of "wfOpenElement" to "Xml::openElement"
 * Change all occurrences of "wfCloseElement" to "Xml::closeElement"

Hope this helps.