slrnpull: 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/bin/slrnpull - from package: slrnpull

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