uscan: 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/uscan - from package: devscripts

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

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