Can't run psql and other utilities under AIX

I've installed a precompiled version of PostgreSQL 7.1.2 on AIX and I
managed to get the database up and running.  When I try to run "psql" and
other commands like "createdb", I get the following:

exec(): 0509-036 Cannot load program psql because of the following errors:
        0509-150   Dependent module
/usr/local/lib/libreadline.a(libreadline.so) c
ould not be loaded.
        0509-152   Member libreadline.so is not found in archive

The library libreadline.a and libreadline.so (linked to libreadline.so.4) do
exist in /usr/local/lib. I tried setting LD_LIBRARY_PATH and LIBPATH, but I
get the same problem.

Any suggestions?

Derek