memcerror: 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/memcerror - from package: libmemcached-tools

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