cgexec: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/bin/cgexec - from package: libcgroup

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/cgexec - from package: cgroup-tools

You may install the required package with command apt-get install {package}

Error in other languages:
cgexec: bevel nie gevind nie
cgexec: comandă negăsită
cgexec: comando não encontrado
cgexec: commande introuvable
cgexec: command not found
cgexec: käsku ei ole
cgexec: không tìm thấy lệnh
cgexec: komanda nerasta
cgexec: Kommando nicht gefunden.
cgexec: kommandot finns inte
cgexec: komut yok
cgexec: nie znaleziono polecenia
cgexec: níor aimsíodh an t-ordú
cgexec: no se encontró la orden
cgexec: no s'ha trobat l'ordre
cgexec: opdracht niet gevonden
cgexec: parancs nem található
cgexec: perintah tidak ditemukan
cgexec: príkaz nenájdený
cgexec: příkaz nenalezen
cgexec: команда не найдена
cgexec: командата не е открита
cgexec: 命令找不到
cgexec: コマンドが見つかりません