latexdiff-cvs: 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-cvs - from package: latexdiff

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

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