retrace-server-worker: 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/retrace-server-worker - from package: retrace-server

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

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