i cant access my account Please Help!

From the Tiberium Alliances FAQ:

All the EA sites use the same login details, if you try using different details on different EA sites then conflicts can occur, the best way to change the password is to go to the central EA site at http://profile.ea.com and change it there. There should be a forgotten password link on the page if you have forgotten your old password that will allow you to specify your email address to be able to set up a new one.

You should then be able to login to any EA site with the email and password you have set up there, occasionally it may not update for all the individual sites immediately in which case you should change the password on the individual site to match the one that you have set up at http://profile.ea.com

Hope this helps. 🙂

Error 500 is a server-side error. Usually, just refreshing the page and clearing your cache and cookies should do the trick and allow you to log back in and play, but sometimes it doesn't work.

There isn't anything you can do to alleviate this, really.