imwcs: 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/imwcs - from package: wcstools

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

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