I also wrote this warning on https://www.facebook.com/groups/BobsTrackBuilder/ Small warning when making xp-packs. I found out that windows can create jpg extensions written in capitals. For example door1.JPG! Try to find a file explorer which shows you how the extensions are written. When you convert door1.JPG to a *.dds file and import it into xp-packer, you could be faced with 2 converted jpeg-files. Here: door1.jpg file and door1.JPG, while only one door1.dds file is available. This can cause the xp-pack to crash in BTB!