Ok now do these steps and let me if you can access the site or not.
1. Go to BPS Custom Code and click the Delete button to delete all custom htaccess code that is currently in BPS Custom Code.
2. Add this code below in this BPS Root Custom Code text box: CUSTOM CODE BPSQSE BPS QUERY STRING EXPLOITS
3. Click the Save Root Custom Code button.
4. Go to the Security Modes page, click the Create secure.htaccess File AutoMagic button, select the Activate Root Folder BulletProof Mode Radio button and click the Activate|Deactivate button.
# BEGIN BPSQSE BPS QUERY STRING EXPLOITS
# The libwww-perl User Agent is forbidden - Many bad bots use libwww-perl modules, but some good bots use it too.
# Good sites such as W3C use it for their W3C-LinkChecker.
# Use BPS Custom Code to add or remove user agents temporarily or permanently from the
# User Agent filters directly below or to modify/edit/change any of the other security code rules below.
RewriteCond %{QUERY_STRING} (sp_executesql) [NC]
RewriteRule ^(.*)$ - [F]
# END BPSQSE BPS QUERY STRING EXPLOITS