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

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

On Debian possible default full paths are:

/usr/bin/qdel - from package: slurm-wlm-torque

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

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