In response to grange at club-internet dot fr:
There are a couple of errors in the mod_rewrite directives given. I found that the following works:
RewriteEngine on
RewriteCond %{ENV:REDIRECT_STATUS} !200
RewriteRule ^cgi-bin/php.cgi - [F]
I removed the = from the RewriteCond and took out the leading / from the RewriteRule.