imcatalog: 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/imcatalog - from package: wcstools

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

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