php.ini setting

I'm trying to set magic quotes Off as my reading tells me that it's not good to have it defaulted to On. My ISP has this setting (from PHPINFO call): magic_quotes_gpc on From reading the php.net manual I found this line php_flag magic_quotes_gpc on which it says to place in the .htaccess file. I downloaded that file from my server's public_html folder, edited it to put in the above line (which now says "Off") and re-uploaded it. Boom! My server no longer works - I get "Internal Server Error" "The server encountered an internal error or misconfiguration....." If I re-edit my .htaccess, remove the line and re-upload, everything works fine. So - what am I mis-interpreting about how to accomplish this task?