Please try using this CVS snapshot:

  http://snaps.php.net/php4-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php4-win32-latest.zip

I installed this version using the old ini file - no errors execpt the one reported.
Still, the result of shell_exec is not passed to the variable but displayed on the page with added "

Content-type: text/html
X-Powered-By: PHP/4.4.0-dev

" after the error message.

In my script i control some nt services and therefor i tell shell_exec to execute net start / net stop. If a service has already been started and i attempt to start it again it returns the error "More help is available by typing NET HELPMSG 2182." like in DOS Shell on Windows but this error not passed to the variable.

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

If you want to recieve the error messages append '2>&1' to the end of the command you are executing. This will work on any *nix based system as well as most recent Win32 server oses such as Windows NT and Windows 2000.

Thank you for the tip to add 2>&1 to the command. This prevents any crashed output from beeing sent to the page (take >nul for no output).
The documentation says:
shell_exec --  Execute command via shell and return complete output as string 
and not 
Execute command via shell and return complete output as string only if exectued command is true but crash when false..

However, thank you for your assistance.
Regards,
Bj