The version number is the one i've got when clicking on "About xBoard". I'm using Ubuntu 9.10 AMD64.
On FICS, and when moving with drag and drop, if your opponent surrenders when you have a piece dragged (and not dropped, because you want to move faster), then the next game you will have that piece already dragged, and any place you click, it will settle there, and maybe the square where it was in the last game will become cleared, so if it was in the first two ranks, it means that not only a ghost piece will appear in the middle of the board, but another one will disappear.
The bug is only visual, as you can move to the square occupied by the ghost piece without problem, and if some of your pieces is invisible, you can move it. At the time either of this things happens, the bug is no longer in effect.
I hope you understand me. When it comes to explain this things, my english is usually not enough.