ax25ipd: 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/sbin/ax25ipd - from package: ax25-apps

You may install the required package with command apt-get install {package}
Error in other languages:
ax25ipd: bevel nie gevind nie
ax25ipd: comandă negăsită
ax25ipd: comando não encontrado
ax25ipd: commande introuvable
ax25ipd: command not found
ax25ipd: käsku ei ole
ax25ipd: không tìm thấy lệnh
ax25ipd: komanda nerasta
ax25ipd: Kommando nicht gefunden.
ax25ipd: kommandot finns inte
ax25ipd: komut yok
ax25ipd: nie znaleziono polecenia
ax25ipd: níor aimsíodh an t-ordú
ax25ipd: no se encontró la orden
ax25ipd: no s'ha trobat l'ordre
ax25ipd: opdracht niet gevonden
ax25ipd: parancs nem található
ax25ipd: perintah tidak ditemukan
ax25ipd: príkaz nenájdený
ax25ipd: příkaz nenalezen
ax25ipd: команда не найдена
ax25ipd: командата не е открита
ax25ipd: 命令找不到
ax25ipd: コマンドが見つかりません