It is a little different as it is a service that requires someone actually going to the Western Union location and collecting the payment but if you contact the company who you want to deal with and explain the PayPal/Croatia situation then I am sure they will co-operate.
Western Union have "franchises" all over major cities throughout the world and from their web site you can find any and all of them.
It's just a thought but it has got me through quite a few purchases from overseas and I despise PayPal for the leeches they are!