affcompare: 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/affcompare - from package: afflib-tools

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

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