importexport_binary.x: 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/importexport_binary.x - from package: quantum-espresso

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

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