Waldemar, You need to download and install Impulse from http://impulsedriven.com/
When you login use your username and password for your stardock account. Under "My Software" ObjectDock Plus v2 should appear.
If it does not, you'll need to tell us (in general terms... no account or receipt numbers for your security) how you bought it: Paypal, money order
credit card, etc. so we can help more. If you paid using Paypal go here to unify your accounts: https://www.stardock.com/support/registrations/
If none of these suggestions help, I would send and email to support@stardock.com and put in all the details of your purchase. Then wait until an actual person replies or your problem will be kicked back to the end of the queue.