roundup-xmlrpc-server: 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/roundup-xmlrpc-server - from package: roundup

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

On Debian possible default full paths are:

/usr/bin/roundup-xmlrpc-server - from package: roundup

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