stressapptest: 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/stressapptest - from package: stressapptest

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

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