I suppose that this is kind of late but here goes anyway. The upgrade from PHP3 to PHP4 is causing this error because the directive php_track_vars is no longer needed in the code. As of version 4.0.3 track_vars is automatically turned on, so all you have to do to fix this problem is to remove the <?php_track_vars?> directive from you code and everything will work ( at least this fixed the problem form me with the web based piranha config tool 🙂). I guess that in cases with PHP4 before 4.0.3 you will have to turn on the track_vars option in the /etc/php.ini (default location) file -- if your using windows, I don't know.
