Can't find book in store

My iBook is available in 32 countries and has been for weeks now. I have been contacted by someone in Ireland who would like to purchase the book but cannot find it in the Irish Bookstore or the US Bookstore when he searches for the author "Antony Heljula". I am quite puzzled as I have sold copies of the book in the US and Ireland so it must surely appear. Anyone else had similar problems?