rsattach: 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/rsattach - from package: ax25-tools

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

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