I dont see why Justin wouldn't travel to Croatia. At the end of the day the fans are the people who are making him popular and making him his money, so I believe that it is his duty to visit as many fans as popular. A European tour doesn't sound ridiculous.
I will be honest with you though, when he came to the UK he did act in a very unprofessional manor and was quite rude. He kept the fans waiting for hours before he went on stage and when he did finally appear half the audience had to leave as they were school children and had to make their way home! A lot of the fans left feeling cheated and very disappointed!
He did give a full apology but I think it may take a while for him to regain the trust of his UK fans!
If you want to keep up to date with Bieber information, why not check out his website -
http://www.justinbiebermusic.com/
It has a link to his tour dates, however this summer he is in the US.
Maybe suggest it on his website and hopefully he may read it?