call_xrl: 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/lib/xorp/bin/call_xrl - from package: xorp
/usr/sbin/call_xrl - from package: xorp

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