I was looking into setting up a subscription on ReadBeam this morning and stumbled across this message posted on the ReadBeam blog
In the last few weeks ReadBeam.com has been swamped by new users. This led to ever growing conversion times. Just converting all the morning eDocs currently takes between four and seven hours.
To alleviate the problem I have temporarily suspended signups.
You only tried to sign up a few days before that, I'd guess there was a backlog of requests that never got processed and you won't be able to use the service for the moment.