This should work if you omit the line that says get_currentuserinfo()… it did for me.
Im on wordpress 2.8.4
global $current_user;
$ul = 'Guest';
if ( isset($current_user) )
{
$ul = $current_user->user_login;
$useremail = $current_user->user_email;
}
if ($ul=='') { $ul = 'Guest';}
// it helps to build a string
// of all your output when
// coding in wordpress, this
// way you can control when and where it goes out to the browser...
$outstr = "Hello, ".$ul;