Try doing:
/debug @debug
Then /whois someone, and post the results of the whois query.
If you're running UnrealIRCd, I know that you get a server notice that has the IP in it, however this seems to already be in the script. Post any error messages you get as well.
Apart from that, there aren't any other suggestions I can give you.
I could come to your network and assist you if you wish.
