pci: 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/pci - from package: php-pear-PHP-CompatInfo

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