flash_eraseall: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/sbin/flash_eraseall - from package: mtd-utils

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