update-gdk-pixbuf-loaders: 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-gdk-pixbuf-loaders - from package: gdk-pixbuf2

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

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