If you ever see this in your Apache logs:

Permission denied: /path/to/web/data/html/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable

Think permissions, permissions, permissions. If you have chmod’ed your .htaccess 644 or even 777 and it’s still not working, start traversing up your directory tree and make sure apache can access everything at each level.

Permissions required will depend on the exact server and software setup, but generally something like 755 (drwxr-xr-x) is probably a good start.