mrancid: 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/lib/rancid/bin/mrancid - from package: rancid

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

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