eric4-pluginrepository: 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/eric4-pluginrepository - from package: eric

You may install the required package with command yum install {package}
Error in other languages:
eric4-pluginrepository: bevel nie gevind nie
eric4-pluginrepository: comandă negăsită
eric4-pluginrepository: comando não encontrado
eric4-pluginrepository: commande introuvable
eric4-pluginrepository: command not found
eric4-pluginrepository: käsku ei ole
eric4-pluginrepository: không tìm thấy lệnh
eric4-pluginrepository: komanda nerasta
eric4-pluginrepository: Kommando nicht gefunden.
eric4-pluginrepository: kommandot finns inte
eric4-pluginrepository: komut yok
eric4-pluginrepository: nie znaleziono polecenia
eric4-pluginrepository: níor aimsíodh an t-ordú
eric4-pluginrepository: no se encontró la orden
eric4-pluginrepository: no s'ha trobat l'ordre
eric4-pluginrepository: opdracht niet gevonden
eric4-pluginrepository: parancs nem található
eric4-pluginrepository: perintah tidak ditemukan
eric4-pluginrepository: príkaz nenájdený
eric4-pluginrepository: příkaz nenalezen
eric4-pluginrepository: команда не найдена
eric4-pluginrepository: командата не е открита
eric4-pluginrepository: 命令找不到
eric4-pluginrepository: コマンドが見つかりません