XF 1.1 Tiny Redirection Problem [vB4 + vbSEO -> xF]

I have followed the directions as outlined here: http://xenforo.com/community/threads/redirects-for-vbseod-urls.5098/

It seems to be working with one small exception...

The URL is getting translated into: http://www.site.com//threads/4235

When I delete the extra '/' the translation works perfectly... how do I get it to remove the extra / automatically?

RewriteEngine on
RewriteRule [^/]+/([\d]+)-.+-([\d]+).html showthread.php?t=$1&page=$2 [NC,L]
RewriteRule [^/]+/([\d]+)-.+.html showthread.php?t=$1 [NC,L]
Any ideas?