memory_compare: 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/lib/plainbox-providers-1/checkbox/bin/memory_compare - from package: plainbox-provider-checkbox

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

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