Shawn recommend for preventing santy that as i as i know that htaccess file prevent infamous browser access to the website. am i correct? And, it may close the access to googlebot, msnbot, yahoobot ..etc?
This shouldn't affect robots at all, unless they're indicated. It's preventing the user agent lwp (which is a perl module that can be used with a script to get files) from accessing your site.
This work-around does not work against today's new Santy variant which spoofs User-Agent. Also, Santy appears to exploit the phpBB highlight vulnerability -- but may not exploit the php unserialize vulnerability.