I "tailed" var/log/messages and I do see no relevant error-messages.
I will try to install Photopost on a Centos-Server.
A php-"script" as "phpinfo.php" being situated in the same directory as "photopost" is running. "install.php" just gives back a blank screen with "done".
In "/var/log/messages" I do not see any error-messages.
My problem is that except seing the blank screen after calling "install.php" tha I do not get ANY ERROR messages. Just the blank screen with "done".
Because of that situation I am not able to send you any error messages from the system-log.
All the best,