noob question: php developing dll error

I am getting the following error

Warning: mymodule: Unable to initialize module Module compiled with debug=0,
thread-safety=1 module API=20020429 PHP compiled with debug=0,
thread-safety=1 module API=20010901 These options need to match in
c:\apache\htdocs\test\test_script.php on line 3
Module mymodule is not compiled into PHP


my php file looks like this

<?
if(!extension_loaded('mymodule')) {
dl('project1.dll');
}


$module = 'mymodule';

if (extension_loaded($module)) {
$str = "module loaded";
} else {
$str = "Module $module is not compiled into PHP";
}
echo "$str\n";

$functions = get_extension_funcs($module);
//echo $functions;
//echo "Functions available in the $module extension:<br>\n";
//foreach($functions as $func) {
// echo $func."<br>\n";
//
//}

?>



Can anyone help?

TIA, David