svnbackport: 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/svnbackport - from package: kdesdk

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

On Debian possible default full paths are:

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

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

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