Fatal error: Call to a member function fetch_userinfo() on a non-object

[dotlyne]

Hi, My forum went off today (VB5.0.5). No any upgrade made, nothing changed... I just woke up with this message on my url
Fatal error: Call to a member function fetch_userinfo() on a non-object in /home/forum/public_html/core/vb/library/user.php on line 722

I have checked that line 722, and I realy dont see anything or havent been able to realize the problem

here is the code from line 714 to 733
***/
public function clearChannelPerms($userid)
{
unset($this->groupInTopic[$userid]);
}

public function updateEmailFloodTime()
{
$usercontext = vB::getCurrentSession()->fetch_userinfo();
if ($usercontext['userid'])
{
vB::getDbAssertor()->update('user', array("emailstamp" => vB::getRequest()->getTimeNow()), array("userid" => $usercontext['userid']));
vB_Cache::instance(vB_CACHE::CACHE_LARGE)->event(array('userChg_' . $usercontext['userid']));
}
else
{
// Guest. Update the field for its session
vB::getCurrentSession()->set('emailstamp', vB::getRequest()->getTimeNow());
vB::getCurrentSession()->save();
}
}

Thanks