wml help,please!

Dear phpers, I'm new to wml. And I got such problem: I can browse my wml page with opera. But when I use my Nokia 7650, I always get unknown reply error. My server is redhat 9, My php is 4.2 The following is one of my test page. <?php Header("Content-type: text/vnd.wap.wml; charset=UTF-8"); Header("Cache-Control: Max-age=1800"); /* header("Expires: 0"); Header("Cache-Control: no-cache, must-revalidate"); */ echo '<?xml version="1.0" encoding="UTF-8"?>'; echo '<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.3//EN" "http://www.wapforum.org/dtd/wml3.dtd">'; echo '<wml> <card>'; //test echo "php"; echo ' </card> </wml>'; ?> Any help would be appreciated. Sincerely, Kun