ltsview: 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/ltsview - from package: mcrl2

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

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