cvsbackport: 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/cvsbackport - from package: kdesdk

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

On Debian possible default full paths are:

/usr/bin/cvsbackport - from package: kdesdk-scripts

You may install the required package with command apt-get install {package}

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