imsmooth: 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/imsmooth - from package: wcstools

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

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