update-gio-modules: 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/update-gio-modules - from package: glib2

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

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