I'm trying to get sound working on an Acer Revo R3600 which has Ubuntu Server (i.e. no GUI) installed on it.

When I run something like mplayer I see (among other things):-

AO: [pulse] Init failed: Connection refused Failed to initialize audio driver 'pulse'

This happens even when mplayer is run as root (and anyway I have added the relevant users to the audio group).

It's the only significant difference I can see between this system and other systems where mplayer works OK.

Google hasn't helped much.

Does anyone have any idea what may be wrong?