htaccess [b] tag

This line of code works fine on my old server:

RewriteRule ^([^/\.]+)/?$ index.php?promo=$1 [L,B]

But on the new server, i figured out that the 'B' at the end causes error 500, thus NOTHING works

So i have to do this:

RewriteRule ^([^/\.]+)/?$ index.php?promo=$1 [L]

The thing is that I really need that B. Does anyone know whats going on here? Is this an apache version thing or something?

Also, what is the term for this feature? I think its called a B flag, but im not 100% sure about that.

Any advice would be appreci开发者_如何学运维ated

[B] didn't get added to Apache until 2.2.7. So if you are only upgrading from 2 to 2.2.x where x < 7, then that'd explain things.