callpass: 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/bin/callpass - from package: xastir

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

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