/blog url yields Sorry, that page could not be found.

I have recently installed the blog add on and the url /blog gives me the Sorry, that page could not be found.. However /blog/index.php does work. I have Modrewrite on and this .htaccess in the main folder

# Perch Runway
RewriteEngine On
RewriteCond %{REQUEST_URI} !^/perch 
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .* /perch/core/runway/start.php [L] 

What could be causing this, I'd like to be able to get to /blog?

Thanks

Perch Runway: 2.8.31, PHP: 5.5.35, MySQL: 5.6.30, with PDO
Server OS: Darwin, apache2handler
Installed apps: content (2.8.31), assets (2.8.31), categories (2.8.31), perch_blog (5.0)