Could someone explain to me why the following works with the 7110 and the mobile browser, but not with the 6210 or 3330. I am using Nokia Internet Toolkit 3.1. I am new to WAP so any help will be appreciated.

header("Content-type: text/vnd.wap.wml"
echo ("<?xml version=\"1.0\"?>\n"
echo "<!DOCTYPE wml PUBLIC \"-//WAPFORUM//DTD WML 1.1//EN\"" . " \"\">";

<card id="card1" title="PHP WML Test">
<p align="center">
Program Test:<br/>

When i run it through the 6210 and 3330 i get the following error "File Format Unknown" and "Unknown File Content".