plperl/createlang issue

I'm trying to load plperl to experiment with it in 7.3.4 with perl v5.8.0.
I've basically tried the following:

configure --with-perl, then
initdb, then
start postmaster, then
createlang plplerl template1

No matter what I try, I keep getting this error:

$ createlang plperl template1
ERROR: Load of file /opt/pgsql/installs/postgresql-7.3.4/lib/plperl.so
failed: libperl.so: cannot open shared object file: No such file or
directory
createlang: language installation failed

But it sure looks like its there to me:

$ ls -l /opt/pgsql/installs/postgresql-7.3.4/lib/plperl.so
-rwxr-xr-x 1 pg pg 35770 Nov 11 19:39
/opt/pgsql/installs/postgresql-7.3.4/lib/plperl.so*

I *think* my perl is threaded based on perl -v:

$ perl -v

This is perl, v5.8.0 built for i386-linux-thread-multi
...

Any clues for the clueless?

TIA.

Ed