When switching a virtual server to use the new PHP CGI wrapper, the PHPSurveyor script no longer has the ability to do a survey. The server owner is also the owner of all the files in the PHPSurveyor script directory, so this does not appear to be a typical user permissions issue.
The admin interface does continue to function, but when a user attempts to do a survey, none of the questions are displayed. Further, there are hundreds errors in the Apache error log, such as:
PHP Notice: Undefined index: grouplist in .../public_html/phpsurveyor/group.php on line 80
PHP Warning: Invalid argument supplied for foreach() in .../public_html/phpsurveyor/index.php on line 405
PHP Notice: Undefined index: totalsteps in .../public_html/phpsurveyor/group.php on line 428
These errors all appear to stem from this one:
PHP Warning: session_start(): open(/var/lib/php/session/sess_xxxx, O_RDWR) failed: Permission denied (13) in .../public_html/phpsurveyor/index.php on line 38
So, I think the problem is that PHPSurveyor expects to be able to write to this session directory, which it can do fine when PHP is running as Apache. However, it has no permissions to this directory as the virtual server owner.