It was
RewriteBase /
RewriteCond %{HTTP_HOST} ^msl37.org$      [NC]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^.*$ http://www.msl37.org/$1 [L,R]

It is
RewriteBase /
RewriteCond %{HTTP_HOST} ^msl37.org$      [NC]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d [OR]
RewriteCond %{REQUEST_URI} /
RewriteRule ^.*$ http://www.msl37.org/$1 [L,R]