mincdiff: 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
/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/mincdiff - from package: minc-tools

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