hg-fast-export: 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/hg-fast-export - from package: hg-fast-export

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

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