tmpreaper: command not found

Have You tried accessing the binary with the full path?

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/sbin/tmpreaper - from package: tmpreaper

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