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

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

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