tester: 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/lib/wims/bin/tester - from package: wims

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

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