Try signing in to digitalpublishing.acrobat.com.
I have and it works fine.
Did you also choose Help > Update in CS6?
Yes, I have run the updater on multiple occasions and there are no updates available.
I'm running a trial version of InDesign 6 that was download, updated and worked fully on Friday. I'm currently waiting for my educational purcahse of the Creative Cloud to be approved, which I ordered Friday morning.
I updated one folio to the v20 Content Viewer Friday afternoon then closed the program from 1PM Friday til 7AM Saturday. Immedately upon opening the folio builder panel would not log-in. I have closed the program multiple times, checked for updates and signed in everywhere else possible. I have access to three different DPS usernames, none of which will sign-in in InDesign 6, but all of which work in InDesign 5.5.
I don't think it matters, but for reference I am running the Mac version of InDesign on a 2007 MacBook Pro with 4GB of RAM and a 2.2 GHz Intel Core Duo processor. There is suffient hard drive space to run the program.