The article doesn't talk about dockzip files. With the dockzip, just double click it and it will place the files in the ObjectDock Library, located in your my documents foler (hopefully). Then, follow Island Dogs article and you should be golden.  

to open a dockzip file, the best thing to do is open the objectdock settings window, then on the left click on themes, then click the import a package button, once the browse window opens navigate to where you saved the dockzip and click it. usually a window will open asking you to agree to something then the contents of the dockzip will be extracted and placed in your objectdock library. for other background just place then in your objectdock library manually, this can be found in my documents...stardock...object dock library and then in the corrosponding folder. eg backgrounds etc etc. once you have done that the background should then be avaliable in the background select section of objectdock. (you may have to close the settings window and then reopen it for them to appear). i hope this helps you