vtk6python: 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/vtk6python - from package: python-vtk6

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

Error in other languages:
vtk6python: bevel nie gevind nie
vtk6python: comandă negăsită
vtk6python: comando não encontrado
vtk6python: commande introuvable
vtk6python: command not found
vtk6python: käsku ei ole
vtk6python: không tìm thấy lệnh
vtk6python: komanda nerasta
vtk6python: Kommando nicht gefunden.
vtk6python: kommandot finns inte
vtk6python: komut yok
vtk6python: nie znaleziono polecenia
vtk6python: níor aimsíodh an t-ordú
vtk6python: no se encontró la orden
vtk6python: no s'ha trobat l'ordre
vtk6python: opdracht niet gevonden
vtk6python: parancs nem található
vtk6python: perintah tidak ditemukan
vtk6python: príkaz nenájdený
vtk6python: příkaz nenalezen
vtk6python: команда не найдена
vtk6python: командата не е открита
vtk6python: 命令找不到
vtk6python: コマンドが見つかりません