In addition, your made-up FEN may be a part of it. As it stands, you have described a position where castling kingside is not a legal move, so perhaps the program wants to develop the king's rook. 

Have a look at [Wikipedia page on FEN][1] or similar resources to see how you can include castling.


  [1]: https://en.wikipedia.org/w/index.php?title=Forsyth%E2%80%93Edwards_Notation&oldid=954773673