Your link is broken.
It sounds like the PHP parser is not being invoked. For
.php files, this is unusual (unless your web host does not support php).
PHP files with a
.tpl extension should work fine if they are
included via PHP. Such files aren’t generally intended to be accessed directly.
Invoking the PHP parser can usually be done via your
AddHandler php5-script .php .tpl
However, you should ask your web host before trying anything.