rdf2ith: 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 CentOS possible default full paths are:

/usr/bin/rdf2ith - from package: nasm-rdoff

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

On Debian possible default full paths are:

/usr/bin/rdf2ith - from package: nasm

You may install the required package with command apt-get install {package}
Error in other languages:
rdf2ith: bevel nie gevind nie
rdf2ith: comandă negăsită
rdf2ith: comando não encontrado
rdf2ith: commande introuvable
rdf2ith: command not found
rdf2ith: käsku ei ole
rdf2ith: không tìm thấy lệnh
rdf2ith: komanda nerasta
rdf2ith: Kommando nicht gefunden.
rdf2ith: kommandot finns inte
rdf2ith: komut yok
rdf2ith: nie znaleziono polecenia
rdf2ith: níor aimsíodh an t-ordú
rdf2ith: no se encontró la orden
rdf2ith: no s'ha trobat l'ordre
rdf2ith: opdracht niet gevonden
rdf2ith: parancs nem található
rdf2ith: perintah tidak ditemukan
rdf2ith: príkaz nenájdený
rdf2ith: příkaz nenalezen
rdf2ith: команда не найдена
rdf2ith: командата не е открита
rdf2ith: 命令找不到
rdf2ith: コマンドが見つかりません