First of all, don't use 'root' for normal day-to-day stuff. It's Bad, for very good reasons.
Second, while I confess I don't know how to fix your problem, a search in Google for 'nmblookup' turned up pages claiming it's part of the Samba-suite, and is used for looking up NetBIOS computer names using NetBIOS-over-TCP/IP queries. Not hindered by any knowledge whatsoever, I think this means there's a program which is trying to find some Windows-running computers, and complains bitterly when it fails. I would start by looking at what is running in the background when you start up KDE ('ps ax'), see if there's something Samba-related activity going on. Then I'd do a search with 'grep' in /etc/ for anything containing 'nmblookup' and try to work out if it's called or not. Looking at the crontab ('crontab -l') might help out too. Whatever the cause, I would be most surprised if it was KDE-related at all. Good luck.
