minc_modify_header: 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/minc_modify_header - from package: minc-tools

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

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