You can add extra Admins using the WebAdmin interface, if you haven't already done so here's how (stop the server first) :
Got to this section of the .ini and change the highlighted lines:
[Engine.GameInfo]
GoreLevel=2
MaxSpectators=2
MaxPlayers=16
AutoAim=1.000000
GameSpeed=1.000000
bChangeLevels=True
bStartUpLocked=False
bNoBots=False
bAttractAlwaysFirstPerson=False
NumMusicFiles=13
bEnableStatLogging=False
HUDType=Engine.Hud
MaxLives=0
TimeLimit=0
GoalScore=0
GameStatsClass=IpDrv.MasterServerGameStats
SecurityClass=UnrealGame.UnrealSecurity
AccessControlClass=Engine.AccessControl
VotingHandlerType=xVoting.xVotingHandler
Change this to:
AccessControlClass=XAdminAccessControlIni
Restart the server, but please note that when you login to the WebAdmin, the username and password will both be changed to "Admin"
You will then be able to add extra Admins, adjust their privs. and of course change your own username and password to whatever you like.