Ok then take a look at the root .htaccess file by going to the BPS Edit/Upload/Download tab page. Click on the "Your Current htaccess File" tab and verify that an .htaccess file really exists and that it is really a BPS .htaccess file. You can compare the "secure.htaccess" file to the root .htaccess file by clicking on the relevant tabs.
Some Hosts (only a few out of 1,000's Worldwide) will do things like replace the BPS .htaccess files automatically with the Host's .htaccess files or delete them entirely or crash your website because you are not using one of their .htaccess files.
Please post this information below about your website. You will find this information on the BPS System Info page.
DNS Name Server:
Which web Host do you have?
Does your Host use cPanel?