dcopclient: 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/dcopclient - from package: kdelibs3

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

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