fpcalc: 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/fpcalc - from package: libchromaprint-tools

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

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