rfmkdir: 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 CentOS possible default full paths are:

/usr/bin/rfmkdir - from package: dpm

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/rfmkdir - from package: dpm

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

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