rem: 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/rem - from package: remind

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

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