a56-toomf: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/a56-toomf - from package: a56

You may install the required package with command apt-get install {package}
Error in other languages:
a56-toomf: bevel nie gevind nie
a56-toomf: comandă negăsită
a56-toomf: comando não encontrado
a56-toomf: commande introuvable
a56-toomf: command not found
a56-toomf: käsku ei ole
a56-toomf: không tìm thấy lệnh
a56-toomf: komanda nerasta
a56-toomf: Kommando nicht gefunden.
a56-toomf: kommandot finns inte
a56-toomf: komut yok
a56-toomf: nie znaleziono polecenia
a56-toomf: níor aimsíodh an t-ordú
a56-toomf: no se encontró la orden
a56-toomf: no s'ha trobat l'ordre
a56-toomf: opdracht niet gevonden
a56-toomf: parancs nem található
a56-toomf: perintah tidak ditemukan
a56-toomf: príkaz nenájdený
a56-toomf: příkaz nenalezen
a56-toomf: команда не найдена
a56-toomf: командата не е открита
a56-toomf: 命令找不到
a56-toomf: コマンドが見つかりません