Auto Proxy Config With Pac File

I've been trying to resolve this for the past hour but I'm getting nowhere.

I'm trying to have a pac file autoconfig proxy settings but it's not working.

I also tested it with a valid pac file that I know works just to see if it was my code, but it failed too.

I'm suspecting it's something I've missed when setting up apache but not sure.

I've got an .htaccess file in the same folder with…

AddType application/x-ns-proxy-autoconfig .pac

Does anybody have any ideas what I maybe missing?

Thanks

L