convert_warp: 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/lib/cmtk/bin/convert_warp - from package: cmtk

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

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