Maybe you followed a dead link or your downloadkey has expired (only valid for about 1-2 hours).
Another reason could be that you try to use a proxy for downloading - and are surfing the web without a proxy. Using the same IP address is essential.
This download is protected, so only visitors from www.dxmartin.at can download. If you came from a different website, please inform the webmaster of this website that hot-linking is prohibited and he needs to link to the download site on www.dxmartin.at instead!
Sorry for any inconvenience
dxMartin