Take a look at this line:
header("Location: <a href="http//www.beitickets.com/index.php?login_error=1" target="_blank">[url]http://www.beitickets.com/index.php?login_error=1[/url]</a>");
//IT SHOULD BE:
header("Location: [url]http//www.beitickets.com/index.php?login_error=1[/url]");
You do not need to use the < a href tags inside of header: location