Activation is currently not possible for this product since the official website is discontinued. In fact, the domain where the data was stored is now expired. The same goes for hosting and activation servers. Unfortunately, you won't have the possibility to activate the the program anymore, now or in the close future unless the developers makes a "360 degrees move" and comes back online with his own software, which is likely to happen.
You will need another inventory application as this one can't be used, purchased, or activated.
Here is a list with some alternatives: http://software.informer.com/search/inventory