Strange behavior on backtick operator execution environment

Hi guys I have upgraded from PHP 4.2.2 to PHP 4.3.0 and some of my php script got broken due to that. This scripts use backticks to execute functions, the problem is the environment where that functions are executed. I have this test code: <?php $dir=pwd; echo "I am on directory: $dir"; ?> If I execute this code using PHP 4.2.2 I get this result: root@test:/root# php /var/www/html/test.php I am on directory: /var/www/html If I execute this code using PHP 4.3.0 I get this different result: root@test:/root# php /var/www/html/test.php I am on directory: /root I have not touched php.ini from one version to the other (I'm still using my one), I'm with safe_mode = Off so it should not affect this. Anybody have a clue about if this is a bug or is a feature of the new version? I'm really confused about it. Best Regards