qrunner: 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/lib/mailman/bin/qrunner - from package: mailman

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

On Debian possible default full paths are:

/usr/lib/mailman/bin/qrunner - from package: mailman

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

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