tanto post y no ayuda...
mira amigo es simple.
ve al phpMyadmin
vas a tu base de datos en el foro.
va a la pestaña SQL
y donde este para introducir el texto pones esto
UPDATE mybb_usergroups SET type
='1', title
='Administradores', description
='El grupo en el que están todos los administradores.', namestyle
='{username}', usertitle
='Administrador', stars
='7', starimage
='images/star.gif', image
='/images/clean-group/english/team-administrator.gif', isbannedgroup
='0', canview
='1', canviewthreads
='1', canviewprofiles
='1', candlattachments
='1', canpostthreads
='1', canpostreplys
='1', canpostattachments
='1', canratethreads
='1', caneditposts
='1', candeleteposts
='1', candeletethreads
='1', caneditattachments
='1', canpostpolls
='1', canvotepolls
='1', canusepms
='1', cansendpms
='1', cantrackpms
='1', candenypmreceipts
='1', pmquota
='0', maxpmrecipients
='0', cansendemail
='1', maxemails
='0', canviewmemberlist
='1', canviewcalendar
='1', canaddevents
='1', canbypasseventmod
='1', canmoderateevents
='1', canviewonline
='1', canviewwolinvis
='1', canviewonlineips
='1', cancp
='1', issupermod
='1', cansearch
='1', canusercp
='1', canuploadavatars
='1', canchangename
='1', showforumteam
='1', usereputationsystem
='1', cangivereputations
='1', reputationpower
='2', maxreputationsday
='0', attachquota
='0', cancustomtitle
='1', canwarnusers
='1', canreceivewarnings
='1', maxwarningsday
='0', canmodcp
='1', canmanagecomments
='1', cansendcomments
='', caneditselfcomments
='', candeleteselfcomments
='', myplaza_rate
='1', myplaza_income_rate
='1' WHERE gid='4'
y le das en ejecutar o algo asi y listo