各位好，我在j2me 联网时发送了xml语句后服务器返回了http 500,不知如何解决，请诸位帮忙，谢谢了！！！

HttpConnection c= (HttpConnection)Connector.open("http://www.coobee.cn/MobileBookServer/",Connector.READ,true);//连接网络
c.setRequestProperty("encode", "UTF-8");
c.setRequestProperty("Content-Language", "en-US" );
c.setRequestProperty("Connection", "keep-alive");
c.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
c.setRequestMethod(HttpConnection.POST);
String postmsg = "readerlogin";
out = c.openOutputStream();
out.write(postmsg.getBytes());
int state = c.getResponseCode();
state=500?????????????

HTTP 500 - 内部服务器错误

这是服务器的错误