I have tried it in IE as well (ewwwww filthy) as I did not feel like downloading another browser. The exact same error persists. Please note that Tiapriestess, who does Mac Tech Support, has the same issue on three different browsers. Same results.
There is also someone who posted, using a different account, on the D3 Web Bug forums. http://us.battle.net/d3/en/forum/topic/6678848032
Seems the folks there ticketed and called, but got no answers about the issue. This makes it seem as though it is not related to our browsers or computers, but is related to the accounts.
Vasala - I have not touched the D3 PTR. I was on the D3 beta before full game release, but that should not affect anything I don't think..but I am reconsidering.
Edit to add a summary
-Issue exists across platforms (PC and Mac)
-Issue exists across browsers (IE, Firefox (multiple versions), Safari)
-Clearing cache, cookies, restarting browser does not help
-Issue exists for both D3 PTR and NON-PTR folks
-Logging in to a different account from the same PC works so it is not user PC specific.
-Those with the issue have full D3 accounts in good standing
-Those affected are left in an odd limbo state as though we are logged in but it does not recognize our D3 account status or battletags for posting access
-WoW and Account Mgt work perfectly so it is not the whole battle.net site
-Forms for SC II properly have my first name in the top right and tell me I have no characters there.
I am wondering if maybe those of us who were in Beta are the ones with the issue...was it pulling our forum login from that beta access and now that they opened the PTR they changed something?