x86dis: 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:

/usr/bin/x86dis - from package: x86dis

You may install the required package with command apt-get install {package}
Error in other languages:
x86dis: bevel nie gevind nie
x86dis: comandă negăsită
x86dis: comando não encontrado
x86dis: commande introuvable
x86dis: command not found
x86dis: käsku ei ole
x86dis: không tìm thấy lệnh
x86dis: komanda nerasta
x86dis: Kommando nicht gefunden.
x86dis: kommandot finns inte
x86dis: komut yok
x86dis: nie znaleziono polecenia
x86dis: níor aimsíodh an t-ordú
x86dis: no se encontró la orden
x86dis: no s'ha trobat l'ordre
x86dis: opdracht niet gevonden
x86dis: parancs nem található
x86dis: perintah tidak ditemukan
x86dis: príkaz nenájdený
x86dis: příkaz nenalezen
x86dis: команда не найдена
x86dis: командата не е открита
x86dis: 命令找不到
x86dis: コマンドが見つかりません