FreePBX 2.3 - Can't play system recording

I’ve just been trying to make up an announcement from the installed sound files.

I found a file that looked suitable in ‘Built-in recordings’ and added it.

I then went back to System Recordings, selected the ‘new’ file and clicked the Play button at the right of it’s name.

I got this:

You don’t have permission to access /admin/modules/recordings/popup.php on this server.

I’ve checked all the file permissions, both under /var/www/admin/ and /var/lib/asterisk/sounds/
Everything is owned by asterisk and all permissions seem consistent.

It looks like apache could be blocking access to the file popup.php ??
(I’m logged in as a user with full admin access, there should not be any restrictions as far as I can tell).

The system is running on CentOS 4 with Asterisk 1.4.13 & FreePBX fully updated.