Make sure you have the following in your nsd.tcl:
# This is where this server's private Tcl library is. All .tcl files in this directory
# are parsed when AOLserver starts. The crucial procedures used in OpenACS are
# defined through this library
#
ns_param library "/web/${servername}/tcl"
For a complete nsd.tcl, see http://fslc.usu.edu/openacs (my page, it has a little bug that I need to fix but it works fine since the bug is on a commented line.
Also, make sure that you have this line at the bottom of your nsd.tcl:
#
# To Source OpenACS Config File. You need a yourservername.tcl file in the
# OpenACS parameters dir. e.g.: say your server name is ``server1'' then you'd need a
# file named server1.tcl. (Hint: Rename ad.tcl to yourservername.tcl and edit it.)
#
source /web/${servername}/parameters/${servername}.tcl
ad_parameter is a proc defined in the ACS Tcl library files so you need these two lines to have a working OpenACS system.
