MSN not working - Adium/Mercury/MSN

Since Friday I've not been able to access my MSN account with Adium, Mercury or MSN. I thought initially it might have been a possible known bug with Adium 1.2.1 but as I have the same problem with other software I think it must be local.

Nothing has changed on my MBP that I can think of. The only thing that has changed is that I now connect to my router with a manually set IP rather than DHCP, but I can't see how this will have affected it.

My yahoo and google accounts connect fine. I'm still using Tiger so shouldn't be affected by the Leopard bug.

Does anyone have any ideas?

Thanks,

Adam