Blank pages after fresh installation

I install amember pro on my linux (redhat server, apache) successfully see http://crdd.osdd.net/amember/setup/index.php?step=5 , when I am clicking on any link (like http://crdd.osdd.net/amember/admin/ ), I am getting blank page. Please help.

I just check my access_log file, it is showing http code 500 it means there is a problem in .htaccess implementation. It tried to modify httpd.conf but no luck.

Thanks for help, upgrade of PHP was creating problem, now I will try on new machine with PHP 5.5