latexdiff-svn: 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/latexdiff-svn - from package: latexdiff

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

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