plotcon: 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/plotcon - from package: emboss

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