I had a similar issue with 7.1 but it was always with changing the IP or gateway. When making a change in 'netcfg', not all files would get updated with the new config, so it caused a conflict.
I had problems so often that I saved the tech article on SCO's site:
http://wdb1.sco.com/kb/showta?taid=1...877793&pgnum=1
This may help you in some small way, hopefully.
Basically, I had to do a search on all files which contained the old IP address or the old gateway address, output the names of each file to a list and then edit each file listed with the new 'correct' IP/GW.
I had so many problems with UW 7.1 over the years, but since upgrading to 7.4 in 2005 I haven't had a single issue of any kind.
Good luck!