Right ho, thank you for the swift response and I'll see to installing Google Chrome. Given my history with computers it's far more likely to be something I've buggered up myself than a problem with the tool.
Another update; I've finally manged to make it work, God only knows how, but the colour editing window has appeared at long last!
Nailed it! Now I can finally transform my beloved Lampadati Pigalle into a replica of Leonid Breznev's Citroen SM! Marvellous tool, thank you for the help.