ax25-node: 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/sbin/ax25-node - from package: ax25-node

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

Error in other languages:
ax25-node: bevel nie gevind nie
ax25-node: comandă negăsită
ax25-node: comando não encontrado
ax25-node: commande introuvable
ax25-node: command not found
ax25-node: käsku ei ole
ax25-node: không tìm thấy lệnh
ax25-node: komanda nerasta
ax25-node: Kommando nicht gefunden.
ax25-node: kommandot finns inte
ax25-node: komut yok
ax25-node: nie znaleziono polecenia
ax25-node: níor aimsíodh an t-ordú
ax25-node: no se encontró la orden
ax25-node: no s'ha trobat l'ordre
ax25-node: opdracht niet gevonden
ax25-node: parancs nem található
ax25-node: perintah tidak ditemukan
ax25-node: príkaz nenájdený
ax25-node: příkaz nenalezen
ax25-node: команда не найдена
ax25-node: командата не е открита
ax25-node: 命令找不到
ax25-node: コマンドが見つかりません