Could you try to update one file from svn? (backup the one you have first): http://pubsvn.ez.no/nextgen/stable/4.1/kernel/classes/datatypes/ezxmltext/ezxmloutputhandler.php
As in, I think it's maybe caused by this: http://issues.ez.no/IssueView.php?Id=14328&activeItem=44
Btw, what are you using $DesignKeys:used for? It's highly undocumented, so if your looking for node or view params its maybe better to get them directly using $#node and so on(global variable).
