Server cache expiry time stopping Cache enabler working

I’m having an issue when i set my servers cache age time.

It adds the line below to my htaccess….

RewriteRule .* – [E=Cache-Control:max-age=1209600]

this is fine and normal however in turn this then stops cache enabler working on all pages except for my homepage.

if i delete this line from my htaccess cache enabler appears on all pages on my site.

Any ideas how i can fix this please? i really need my server cache in place but would love for cache enabler to still work with it.

Just cannot figure out why that one line is stopping it.

thanks!