The most likely cause is insufficient permissions to execute system calls in the web server environment.
You need to give the Internet Guest Account (a.k.a. IUSR_MachineName
or simply IUSR) read and execute permission to the command shell program,
cmd.exe
. Typically, permission to this file is explicitly denied as a
security measure.
c:\windows\system32
or c:\winnt\system32
directory.
cmd.exe
, and select Properties....