Bizzare initdb failure: "The program "postgres" is needed by initdb"

Hi all!
I am getting the following error when I am trying to create a database
cluster with initdb :

[root(at)feanor ~/postgresql-8.0.0]# cd /usr/local/pgsql/bin
[root(at)feanor bin]# su postgres
[postgres(at)feanor bin]$ ./initdb -D /usr/local/pgsql/data
sh: /dev/null: Permission denied
fgets failure: Success
The program "postgres" is needed by initdb but was not found in the
same directory as "/usr/local/pgsql/bin/initdb".
Check your installation.

Then initdb exits.
postgres file IS in the same directory, of course.
The permissions on "postgres", as well as on all other files in the
folder,
are rwxr-xr-x, and root is the owner.
"postgres" itself is runnable.
I have reproduced this error with 8.0.0rc2, 8.0.0 and 8.0.1 .
My system is running Red Hat Linux 7.3 (2.4.18).
Unfortunately, reinstalling Linux is out of question - it is a
production
system used 24/7.
Could anyone figure out what is going on?
Thanks!