run-single-task: 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 Debian possible default full paths are:

/usr/bin/run-single-task - from package: ulatency

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

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