qselect: 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/qselect - from package: gridengine
/usr/share/gridengine/bin/lx26-x86/qselect - from package: gridengine

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

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