netrom_call: 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/netrom_call - from package: ax25-tools

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