Remove/rename all .htaccess files, including those that might be in parent directories. Make a simple PHP script:
<?php phpinfo(); ?>
When you browse to it, the page should say it is running as PHP 5.2.6 CGI/FastCGI. Since you have no .htaccess files now and that is a simple script, thats all that should happen. If something else happens (including if it says 4.4.7 or 4.4.9), contact support and inform them you think Apache isn't configured to run PHP 5 correctly. If you try to run your problem script and it still doesn't work then you need to get someone to fix the script (it should output a proper content-type).
Also go to Domains -> Manage Domains and "Edit" the domain so the server config gets refreshed.
Customer since 2000 openvein.org