I have personally installed BPS Pro on websites hosted on IX Hosting so it is not an issue with this Host / Server itself and a conflict with the .htaccess files that come with BPS. So there is some other factor involved here that is specific to your website that is causing this problem.
You can ask your web host support folks what your Server API is. It should be CGI.
The only other thing i can suggest to try next is deactivating all of your other plugins except for BPS, switch your Theme to the WP 2012 Theme and then test and see what happens. Thanks.
If you are using a custom php.ini file on IX Web Hosting then see these custom php.ini setup instructions (if you are not then disregard this) >>> http://www.ait-pro.com/aitpro-blog/2853/bulletproof-security-pro/php-ini-general-and-host-specific-php-ini-information-for-bps-pro/#ix-hosting