After installing Debian 7 wheezy on a KVM server and adding webserver, php, mysql environment (aptitude install php5-mysql mysql-server), I extracted PMA 4.0.3 to the /var/www directory. Without configuring anything, checking it in browser, only the PMA logo shows up, the login form is missing. Firebug shows several JS errors, see attachment.
I repeated the procedure on a Virtualbox VM, result was the same.
Tried 4.0.2, 126.96.36.199, same result.
3.4.11 WORKS (bundled with Debian wheezy)!
4.0.3 works on Debian squeeze, and with XAMPP on Windows. Maybe it's related to the new apache/php version in squeeze.