fl-credential-ctl: 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/fl-credential-ctl - from package: funkload

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

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