Fhelp: 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/Fhelp - from package: ferret-vis

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

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