isotpserver: 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/isotpserver - from package: can-utils

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

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