Logged in once with the new viewer and out; I already seemed to have an account with Vivox but changed password anyway.

On the page where you download the SLim clients click that blue registration button

that will register and you'll be able to log in with SLim within 30 seconds

you will also need to launch the First Look CLient along with SLim to synch the friends list. When both are running, hit the refresh button

on the SLim client

No, I did all that. I already have an existing Vivox registration apparently; the blue button just takes me to a box with my email/password.

I didn't launch the client _at the same time_ as SLim, admittedly, but I can't log in with SLim.

we will see how all this pans out as more people sign up

Also, I can't get a password update: "Failed updating account. Account id not found. ( 1100 )"

There's no linux client for SLim yet

As an update I did try running them simultaneously and it made no difference.

I believe you have to (once) have the new viewer and SLim open, and in SLim hit "refresh"