svnnotify: 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 Debian possible default full paths are:

/usr/bin/svnnotify - from package: libsvn-notify-perl

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

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