I have a code here and I'm having a problem on just 1 line.. What's wrong with this? is this a conflict?

Document doc = new Document();
Element root = doc.createElement( "" , "root");
Element element = doc.createElement("", "child");
OutputStream outStream = fconn.openOutputStream();
KXmlSerializer serializer = new KXmlSerializer();
serializer.setOutput(outStream, "UTF-8");

doc.write(serializer); // the problem is here saying (method write in class org.kxml.kdom.Node cannot be applied to given types,
outStream.close(); REQUIREDrg.kxml.io.AbstractXmlWriter;, FOUND: org.kxml2.io.KXmlSerializer; //

Please help me..