Someone recently posted a very good comment on Slashdot detailing common PHP problems. Several of the replies give solutions to the various issues raised. However most of them involve editting php.ini to use safer options. (Why isn't php-recommended.ini the default config?)
Yes, there are ways around the problems listed. (Drupal, a PHP-based CMS which this site uses, provides quite a few helper-functions designed to make handling those errors much easier.)
However the point remains: when using PHP - be careful. There are quite a few gotchas for unwary coders.