username is already in use or does not meet the administrator

[loffar]

hello ,
i am getting this strange error on my forum

vBulletin Message
That username is already in use or does not meet the administrator's standards. If you are Admin and you have forgotten your password, click here.

i can't login to admin panel even nor any other admins can login ..
i did no changes and suddenly this error came up i have even reuploaded all vbulletin files but it's all useless
can some help me what's causing this problem and how can this be fixed ?

Thanks in advance

 

[Baadshah!]

Clear Ur Browser Cookies Then Try Again.

 

[SpeedRazors]

if that doesn't work do an upgrade /install/upgrade_368.php or whatever version your using