pbesparelm: 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/pbesparelm - from package: mcrl2

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

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