fd2c: 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 CentOS possible default full paths are:

/usr/bin/fd2c - from package: gprolog
/usr/lib64/gprolog-1.3.1/bin/fd2c - from package: gprolog

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/lib/gprolog-iso/bin/fd2c - from package: gprolog

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

Error in other languages:
fd2c: bevel nie gevind nie
fd2c: comandă negăsită
fd2c: comando não encontrado
fd2c: commande introuvable
fd2c: command not found
fd2c: käsku ei ole
fd2c: không tìm thấy lệnh
fd2c: komanda nerasta
fd2c: Kommando nicht gefunden.
fd2c: kommandot finns inte
fd2c: komut yok
fd2c: nie znaleziono polecenia
fd2c: níor aimsíodh an t-ordú
fd2c: no se encontró la orden
fd2c: no s'ha trobat l'ordre
fd2c: opdracht niet gevonden
fd2c: parancs nem található
fd2c: perintah tidak ditemukan
fd2c: príkaz nenájdený
fd2c: příkaz nenalezen
fd2c: команда не найдена
fd2c: командата не е открита
fd2c: 命令找不到
fd2c: コマンドが見つかりません