qembed: 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/lib64/qt-3.3/bin/qembed - from package: qt3-devel
/usr/lib/qt-3.3/bin/qembed - from package: qt3-devel

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

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