Handling 500-Internal Server error caused by lack of authority at the object level

I'm wondering if there's any way to provide a more specific error
message when the call to an RPG CGI program fails due to a lack of
authority to the CGI program.

This is the setup I have now:

I've got some CGI program set up with *PUBLIC *USE, others are set up
*PUBLIC *EXCLUDE.

My Apache configuration file includes the following lines:
           ScriptAliasMatch /melcgip/public(.*).pgm
/qsys.lib/melcgi.lib/$1.pgm
           ScriptAliasMatch /melcgip/protected(.*).pgm
/qsys.lib/melcgi.lib/$1.pgm
           <Location /melcgip/protected>
                AuthName "Protected - iSeries Username required"
                AuthType Basic
                PasswdFile %%SYSTEM%%
                UserID %%CLIENT%%
                Require valid-user
           </Location>
           <Directory /QSYS.LIB/MELCGI.LIB>
                Options None
                order allow,deny
                allow from all
           </Directory>
  
This works the way I want it to.  
--CGI programs accessed via the /melcgip/public/ path don't ask for an
iSeries username and password.  
--CGI programs accessed via the /melcgip/protected/ path do ask for an
iSeries username and password.


If I have a CGI program with *PUBLIC *EXCLUDE named myprog.pgm to which
the QTMHHTP1 and QTMHHTTP profile's don't have authority to either and a
user accidentally types in //my400/melcgip/public/myprog.pgm the see the
rather unhelpful error message:
500 Internal Server Error
Cannot read script output pipe.

Is there anyway to provide a better error message or even better
automatically redirect the correct path of
//my400/melcgip/protected/myprog.pgm?


I suppose I could always split the CGI programs into two separate
libraries, but I'd rather not.  

I suppose I could use have to separate IFS directories with symbolic
links to the actual programs, but that would be more work.

Does anybody out there have any other solutions?


Thanks,

Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121