acorn-fdisk: 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
/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:

/sbin/acorn-fdisk - from package: acorn-fdisk

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