referral link id not work

[hinomaru]

hello..

i'm test using the reflink id like this format : http://myforum.com/register.php?referrerid=aaa
for register MrA
But when i see MrA profile on admincp, the refferral column of MrA is blank, and the user aaa don't have a referral.

is my link for the referral id wrong?or i miss some setting? I already set the referral option to yes on vbulletin option.


Thx

Regards

Rudi