XML parsing in D

I am trying to parse an XML document that stores data for a map in my 2D game. I am trying to do this step by step, I downloaded the file, create a new document parser and selected the start tag and the attribute that I want to extract. However, when I check what the attribute value should be (25) it appears as zero. Telling me that I missed something and it won't pull in the XML value.

This XML file is being processed: http://pastebin.com/tpUU1Wtv

    void LoadMap(string filename)
{
    enforce( filename != "" , "Filename is invalid!" );

    xmlData = cast(string) read(filename);

    enforce( xmlData != "", "Read file Failed!" );

}

void ParseMap()
{
    auto xml = new DocumentParser(xmlData);

    xml.onStartTag["map"] = (ElementParser e)
    {
        mapWidth = to!int(e.tag.attr["width"]);
    };
    xml.parse();
    writeln("Map Width: ", mapWidth);
}