Maybe a flash player update required? Have you got latest browser update? Sorry for mentioning the obvious if you have all this sorted already.
I understand the woes of trying to get this up and running - I had the same earlier on in the week. I sent a good few emails to the old service and the new and found both support very helpful - in the end. It now works seemlessly and I think its far better than SaintsTV. It looks more professional and works more professionally.
I suggest those still having login problems try their existing SaintsTV login user name and the word "password" as the password. I think the new providers have reset the passwords. Mine worked this way. The other snag I had was my email address was my username - my email address is crazy long and wouldn't fit in the username login form... they changed this too so that it would.
Just my experiences... maybe of use.