404 Webmaster Response Code

I've got multiple 404 response code urls in my web master tools so Ive been adding re direct code to the .htaccess file as follows

301 Redirects

301 Redirect 1

RewriteCond %{QUERY_STRING} ^$

RewriteRule ^about-us.html$ /about-our-company.html? [R=301,NE,NC,L]

301 Redirect 2

RewriteCond %{QUERY_STRING} ^$

RewriteRule ^wood-venetian-blinds$ /wooden-blinds/? [R=301,NE,NC,L]

but the old url's are not being re directed.

Have i got the code wrong?