/home/:prodsrv128>sqlldr
exec(): 0509-036 Cannot load program sqlldr because of the following errors:
        0509-130 Symbol resolution failed for sqlldr because:
        0509-136   Symbol pw_post (number 265) is not exported from
                   dependent module /unix.
        0509-136   Symbol pw_wait (number 266) is not exported from
                   dependent module /unix.
        0509-136   Symbol pw_config (number 267) is not exported from
                   dependent module /unix.
        0509-136   Symbol aix_ora_pw_version3_required (number 268) is not exported from
                   dependent module /unix.
        0509-192 Examine .loader section symbols with the
                 'dump -Tv' command.

I had them check everything:

ORACLE_HOME,   ORACLE_SID,  PATH, LD_LIBRARY_PATH  etc... 

They were all set properly and also I had them check the permission settings on the files etc.. .and everything was fine.   I also did a relink all to relink the binaries and still no good.   Then i did search on google and still no good.  Finally i checked metalink and found an article:  1006649.6

Problem Description: 
==================== 
 
You receive the following undefined symbol errors starting Oracle on an IBM
RS/6000 AIX operating system:

     Could not load program oracleSID
     Symbol pw_wait in oracle is undefined
     Symbol pw_post in oracle is undefined
     Symbol pw_config in oracle is undefined
     Error was: Exec format error


Problem Explanation:
====================

Oracle executables (such as SVRMGR, oracle, etc.) on AIX
are built with the assumption that the post-wait extension
is running in the UNIX kernel.  If the extention does not
exist, the above errors will occur. 


Search Words:
=============

post wait, pw-syscall, driver, pwpost, pwconfig, pwwait

The solution was simple:   I had the UNIX SA run the following command:

cd /etc

./loadext -l pw-syscall

That fixed the problem.

Here is what oracle document states:

Solution Description: 
=====================

On most UNIX platforms, Oracle uses semaphores to synchronize shadow processes
and background processes. But with RS/6000 AIX, the post/wait drive is used
instead to increase the performance.

The most common solution is to re-install the kernel extension. The best way
to do this is to apply Patch 2896876 . This patch is designed to clean-up
existing kernel extension, re-install them, and update /etc/inittab to
automatically load the proper extension at boot time. Please review the
patch installation output to determine if a reboot is required

This may be required if rootpre.sh was run more than once.
When rootpre.sh is run, it issues the command:
    ' /etc/loadext /etc/pw-syscall '

The second time this command is issued, the one that is currently
running will be deactivated, thus giving the error above when database is
brought up.  Rebooting the machine will clean out the deactivated
drive in kernel and rerun the system call.

In the 'Tuning Hints and Suggestions', there is a section called the 'Proper
startup of the post/wait driver' which also suggests that rebooting the
machine to resolve the error.

You can also refer to the PW_README file in $ORACLE_HOME/orainst for more
information.

Also, you may want to do the following before rebooting:

1. Login as "root"

2. Change locations to the "etc" directory

     # cd /etc

3. Verify that the "loadext" and "pw-syscall<version>" files exist

     # ls -l loadext
     # ls -l pw-syscall* 

4. Query whether kernel extension is loaded or not:

     # ./loadext -q pw-syscall
   
   If a kernel extension is already loaded, check the version

     # ./loadext -r pw-syscall

   If the kernel extension version is older the the reqested version, unload
   the version before loading the new version

     # ./loadext -u pw-syscall
 
5. Mannually load the kernel extensions 

     # ./loadext -l pw-syscall<version>

6. Invoke Server Manager to see if you still get the error 
   
                                             
Additional Information:                                                       
-----------------------                                                      
                                                                              
From AIX 7.2 Installation and Configuration Guide (Appendix A-34), there is
one kernel extension built in to the Oracle kernel for AIX:            
- Oracle Post-Wait Kernel Extension.                                          
 
Note that starting with Oracle v7.1.6, the Oracle Protected 
Shared Memory Kernel Extension of prior releases has been removed.            
   
The Oracle Post-Wait Kernel Extension implements an optimized mechanism of 
inter-process communications without the overhead of signal handlers or
semaphores.                                                                   
   
During the installation, the following files are placed in the /etc 
directory:  

/etc/pw-syscall                                                               
/etc/loadext                                                                  
 
These files are normally executed automatically at system startup.  
This loads the extension into the kernel and it will remain loaded as long 
as the system is running.

In the second case, reboot your machine. If your "/etc/inittab" file contains
the line:
   
        orapw:2:wait:/etc/loadext /etc/pw-syscall

then the post/wait driver will be loaded when the system is rebooted.    
Otherwise, you will have to carry out the above steps to manually load the
driver.

Thanks,

Hope this helps.