unpack_bootlogo: 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/share/gfxboot/bin/unpack_bootlogo - from package: gfxboot-dev

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

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