[ngIRCd-ML] OPER-command not working?

Hey folks, we are trying to setup ngircd for a support-channel and its working fine so far. That was the easiest configuration of all irc-daemons I could find yet :-). We were even able to link two servers in a minute. Just the following problem arises now, I configured an operator in the config-file. I read in the archives that I should use "/OPER user secret" to activate it. But it tells me "Unknown command: oper", any hint what I may have done wrong? Can't I enter that once I am in a channel? Thanks in advance, Thomas