If you purchased your server with admin mod, it comes enabled.
You can enable Admin mod on the Easy Setup page by making sure its checked under the Metamod section, then hitting commit changes.
If you wish to do it manually, you can edit the addons/metamod/plugins.ini file and uncomment the adminmod line by removing the semicolon (;) like this:
DISABLEwin32 addons/adminmod/dlls/admin_mm.dll
You can disable Admin mon on the Easy Setup page by unchecking the mod under the Metamod section, then hitting commit changes.
If you wish to do it manually, you can edit the addons/metamod/plugins.ini file and comment the adminmod line with a semicolon (;) like this:
;win32 addons/adminmod/dlls/admin_mm.dll