Hi Zoltan!
Thank you for bringing up the issue, is turned out to be a bug – I will definitely include the fix in the upcoming theme update. Meanwhile, you can fix it by downloading these files from our repository: satoristudio.net/files/RPS_fix_12.08.2012.zip, unzipping them to your computer, and uploading via ftp into /wp-content/themes/Fuji/includes/recent-posts-slider folder in your WordPress installation. They should replace the two existing files in that folder.
I hope this helps! If you have other questions, do not hesitate to ask!
Sincerely,
Andrew | Satori