Problems installing RT-Extension-MergeUsers

I’ve got an RT server running (v. 3.4.5) on a FC3 linux machine
successfully. I’m attempting to install RT-Extension-MergeUsers, but
when I run perl Makefile.PL, I’m getting the following error:

Cannot find the location of RT.pm that defines $RT::LocalPath in:
inc /usr/local/lib/perl5/5.8.6/i686-linux-thread-multi-64int-ld /usr/
local/lib/perl5/5.8.6 /usr/local/lib/perl5/site_perl/5.8.6/i686-linux-
thread-multi-64int-ld /usr/local/lib/perl5/site_perl/5.8.6 /usr/local/
lib/perl5/site_perl . /usr/rt /usr/rt/lib /opt/rt3/lib /opt/lib/rt3 /
opt/lib /usr/local/rt3/lib /usr/local/lib/rt3 /usr/local/lib /home/
rt3/lib /home/lib/rt3 /home/lib /usr/rt3/lib /usr/lib/rt3 /usr/lib /
sw/rt3/lib /sw/lib/rt3 /sw/lib

RT is installed in /usr/rt and when I enter /usr/rt/lib when it asks
for the Path to RT.pm, it returns:
Path to your RT.pm: /usr/rt/lib
Cannot find the location of RT.pm that defines $RT::LocalPath in:
inc /usr/local/lib/perl5/5.8.6/i686-linux-thread-multi-64int-ld /usr/
local/lib/perl5/5.8.6 /usr/local/lib/perl5/site_perl/5.8.6/i686-linux-
thread-multi-64int-ld /usr/local/lib/perl5/site_perl/5.8.6 /usr/local/
lib/perl5/site_perl . /usr/rt /usr/rt/lib /opt/rt3/lib /opt/lib/rt3 /
opt/lib /usr/local/rt3/lib /usr/local/lib/rt3 /usr/local/lib /home/
rt3/lib /home/lib/rt3 /home/lib /usr/rt3/lib /usr/lib/rt3 /usr/lib /
sw/rt3/lib /sw/lib/rt3 /sw/lib /usr/rt/lib /usr/rt/lib/rt3/lib /usr/
rt/lib/lib/rt3

What am I missing?
Sorry if this is a newbish question. I’m new to the list and to RT,
but I’ve done plenty of searching around the archives to see if this
was already addressed.

Yerin Kay
Computing Services
Carnegie Mellon