Post is a little bit old but still if you need a reply - you will have to set up a limited liability company here in Croatia. You will have to contact the notary office who will do the neccessary work for you. Your only obligation is to set up a company bank account first and come up with a name and an address for the company. The whole process will require about 25.000 Kuna of which 20.000 is your start up capital and can be spent for the company purposes later.
Contact me if you need help - i just set up a company like that myself.. J