pbs_wish: 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/pbs_wish - from package: torque-gui

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

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