From here yes? : http://sto.perfectworld.com/download
Direct Download perhaps?

If I was in your position, I would:
- temporarily disable my antivirus and firewall software (until after you successfully get into the game)
- update internet explorer web browser to the latest version (if I had Internet explorer web browser)
- clear my internet browser cache (especially internet explorer, if I had it)

Also, the web installer will ask you to install software called: PANDO MEDIA BOOSTER (or similar). This is official software that assists in downloading the game.

Personally, I do not like this, as it remains after installation (and can reportedly slow down your connection to the game). So after installation, if I was in your position, I would uninstall pando media booster from my computer using the windows control panel uninstall menu.

(I'm not sure if I'm making any sense to you, I gather you are a German speaker).