.htaccess rewriterule - please help, quick fix?

hi,

i have the following code to forward something like www.domain.com/something-here to www.domain.com/go.php?go=something-here

it seems to work ok but for some reason when "." is included it doesn't work, e.g. something like www.domain.com/digitalpoint.com doesn't work

RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.domain\.com$ [NC]
RewriteRule ^.*$ http://domain.com%{REQUEST_URI} [R=301]
RewriteRule ^([^/\.]+)/?$ go.php?go=$1 [L]

Code (markup):

any help appreciated - many thanks in advance!