We are running PHP 5.5.9 (NTS, x86) on Windows Server 2012 R2 with FCGI, Kerberos Auth and fastcgi.impersonate = 1. Application Pool runs with a AD User Service Account, W3P Service runs with "local system" Account.

Execution is enabled in IIS Script Handler for FCGI-PHP. Handler Feature Permissions is also set to "Execute".

Now I am trying to run a application from command line, but this also simple commands like dir or ping are failing with "unable to fork".

exec('dir');

Warning: exec(): Unable to fork [dir] in D:\mypath\myfile.php on line 2

I have tried in my DEV-Environment:
- added read+execute Permissions to "Everyone" to c:\windows\syswow64\cmd.exe
- copied c:\windows\syswow64\cmd.exe to PHP-dir
- added read+execute Permissions to ISUSR to cmd.exe im PHP-dir
- added read+execute Permissions to IIS_IUSRS to cmd.exe im PHP-dir
- upgraded to PHP 5.5.16
- watched with sysinternals procmon, found no error or something
- searched hours and hours for this on the web

Any hints? Thank you for your help!