qmod: 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:

/usr/bin/qmod - from package: gridengine
/usr/share/gridengine/bin/lx26-amd64/qmod - from package: gridengine
/usr/share/gridengine/bin/lx26-x86/qmod - from package: gridengine

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

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