cinnamon-session: 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

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/cinnamon-session - from package: cinnamon-session

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