OK I know this thread is old but I have some helpful information I think might help:
1. If you want to use kreds to purchase you have to open the game with Firefox or Chrome. Internet Explorer causes problems from what I heard and using other browsers might also cause problems because as much as I know no one really tested it (or at least didn’t tell anyone about it).
2. I’m not sure about it but I once read somewhere that having the “remember me” box at the login checked might cause problems. So if you still have problems try logging off and then logging on with that box unchecked.