Error while loading shared libraries

Hello,
I have installed postgresql, version 8.3.3. and when I run: su -l postgres
-c "/usr/local/pgsql/bin/createuser -d -a nobody", I get this error:

sh-2.05b# su -l postgres -c "/usr/local/pgsql/bin/createuser -d -a nobody"
/usr/local/pgsql/bin/createuser: error while loading shared libraries:
libz.so.1: cannot open shared object file: No such file or directory

However, this library is there..:
sh-2.05b# su -l postgres -c "echo $LD_LIBRARY_PATH"
/lib:/usr/lib:/opt/IBM-ME-2.2.2/jre/bin:/usr/local/pgsql/lib

sh-2.05b# su -l postgres -c "ls -ls /usr/lib/libz.*"
0 lrwxrwxrwx 1 root root 24 Jul 25 13:46 /usr/lib/libz.so ->
/usr/lib/libz.so.1.2.2.2
0 lrwxrwxrwx 1 root root 24 Jul 25 13:46 /usr/lib/libz.so.1 ->
/usr/lib/libz.so.1.2.2.2
76 -rwxr-xr-x 1 root root 75568 Jul 25 13:45 /usr/lib/libz.so.1.2.2.2
sh-2.05b#

So I was wondering if you guys could help me! I do not know what is wrong
:-(
Is createuser not looking at LD_LIBRARY_PATH for its libraries?
Thanks,
--
- Yuly