rdf2com: 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/rdf2com - from package: nasm-rdoff

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

On Debian possible default full paths are:

/usr/bin/rdf2com - from package: nasm

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

Error in other languages:
rdf2com: bevel nie gevind nie
rdf2com: comandă negăsită
rdf2com: comando não encontrado
rdf2com: commande introuvable
rdf2com: command not found
rdf2com: käsku ei ole
rdf2com: không tìm thấy lệnh
rdf2com: komanda nerasta
rdf2com: Kommando nicht gefunden.
rdf2com: kommandot finns inte
rdf2com: komut yok
rdf2com: nie znaleziono polecenia
rdf2com: níor aimsíodh an t-ordú
rdf2com: no se encontró la orden
rdf2com: no s'ha trobat l'ordre
rdf2com: opdracht niet gevonden
rdf2com: parancs nem található
rdf2com: perintah tidak ditemukan
rdf2com: príkaz nenájdený
rdf2com: příkaz nenalezen
rdf2com: команда не найдена
rdf2com: командата не е открита
rdf2com: 命令找不到
rdf2com: コマンドが見つかりません