The compiler is telling you that XNodeSet has no constructor which takes an Element as its sole parameter. Looking at the code confirms that. There is a constructor which builds an empty XNodeSet (for a specific DTMManager) to which nodes can then be added; that seems to be the closest approximation to what you're tyring to do.
Alternatively, look for a solution which doesn't involve directly manipulating an instance of XNodeSet. If an extnsion function returns an Element (or other DOM Node) from your extension, we will automatically wrap a Node-Set around it before handing it to the rest of Xalan... does that suffice for your needs? (See http://xml.apache.org/xalan-j/extensions.html for details of how arguments and return values are processed.)
