yamcfg: 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/yamcfg - from package: ax25-tools

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

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