Android :: Facebook Connect Android - 104 Incorrect Signature

I am getting "104Incorrect signature ". What should I be setting contentType type as? Should I set as:
String contentType = "application/x-www-form-urlencoded"; or String contentType = "multipart/form-data; boundary=" + kStringBoundary;

HttpURLConnection conn = null;
OutputStream out = null;
InputStream in = null;
try {
conn = (HttpURLConnection) _loadingURL.openConnection();
conn.setDoOutput(true);
conn.setDoInput(true);

if (method != null) {
conn.setRequestMethod(method);
if ("POST".equals(method)) {..............................