lps2lts: 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/lps2lts - from package: mcrl2

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

Error in other languages:
lps2lts: bevel nie gevind nie
lps2lts: comandă negăsită
lps2lts: comando não encontrado
lps2lts: commande introuvable
lps2lts: command not found
lps2lts: käsku ei ole
lps2lts: không tìm thấy lệnh
lps2lts: komanda nerasta
lps2lts: Kommando nicht gefunden.
lps2lts: kommandot finns inte
lps2lts: komut yok
lps2lts: nie znaleziono polecenia
lps2lts: níor aimsíodh an t-ordú
lps2lts: no se encontró la orden
lps2lts: no s'ha trobat l'ordre
lps2lts: opdracht niet gevonden
lps2lts: parancs nem található
lps2lts: perintah tidak ditemukan
lps2lts: príkaz nenájdený
lps2lts: příkaz nenalezen
lps2lts: команда не найдена
lps2lts: командата не е открита
lps2lts: 命令找不到
lps2lts: コマンドが見つかりません