I just installed version 1.3.3 of JoomSEF, and got a 404 error when I changed the startpage from the default Front Page to my own static content.

However, I found an easy way to fix this, and that is by adding the following in joomsef.php, after line 59:
// Fix problem with missing parameters!
parse_str($QUERY_STRING, $args);
while (list($key, $value) = each($args)) {
$_GET[$key] = $_REQUEST[$key] = $value;
}

Would be great if this could make it into the offical release.