It may be the case that your PHP is configured to not support short PHP tags -- the <? ones. The standard PHP tag is <?php, however, many people will still add <? to their code thinking that is the standard.
Try the following 2 lines of code and see what occurs:
<?phpecho'Does this get displayed as PHP or HTML?'; ?> <?echo'Does this get displayed as PHP or HTML?'; ?>
The man who comes back through the Door in the Wall will never be quite the same as the man who went out.