There are known problems with -g support. You should be able to just allow world read and execute on /usr/local/pgsql/lib.
This is one case a from RPM installation is much easier, since libpq is in /usr/lib....but I'm biased, being the PostgreSQL RPM maintainer....
Yes, nsadmin is a member of the group web.
So I did more digging and found this bug with a patch provided, and this other patch. This is a rather surprising bug to go unfixed. Does anyone have experience with either of these patches?