mkdtdskel: 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/mkdtdskel - from package: libxml-dt-perl

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