gfserver: 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/gfserver - from package: gadfly

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

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