OS/X and PL/PGSQL

I am having a very very odd time with PostgreSQL 7.3.2 and PL/PGSQL.  I
am pretty sure that I have a working install of 7.3.2 and PL/PGSQL.
However, I don't now, for reasons which are not clear. I can create a
new database, and try to add PL/PGSQL to it, and the results are as
follows:

[Robin:~] pramsey% createdb pltest
CREATE DATABASE
[Robin:~] pramsey% createlang plpgsql pltest
ERROR:  Load of file /usr/local/pgsql/lib/plpgsql.so failed: no error
message available
createlang: language installation failed

The library file *does* exist, and the permissions are all set so that
the library is readable.  Any ideas on this one?

      Paul Ramsey
      Refractions Research
      Email: pramsey@refractions.net
      Phone: (250) 885-0632