XML performance app problem

I am testing XML performance app. But instead of fetching iTunes xml I have created my a local xml file in the bundle. The content of the file is given below:

<Songs>
    <channel>
        <item>
            <title>
            title
            </title>
            <category>
            category
            </category>
            <itms:artist>
           开发者_StackOverflow中文版 artist
            </itms:artist>
            <itms:album>
            album
            </itms:album>
            <itms:releasedate>
            November 23, 1937
            </itms:releasedate>
        </item>
    </channel>
</Songs>

When I am parsing it with NSXMLParser release date is not showing, everything else is showing properly. But while I am parsing with Libxml2 parser app is crashing showing "Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Unhandled error encountered during SAX parse.'" this on console.