nikon-curve: 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/nikon-curve - from package: ufraw

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

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