Pretty sure it has nothing to do with a gamelogic bug but more about either a denied write access (culprits can be the AV or Windows UAC) or an incompatibility between game engine directX library and your video driver. In both case, you should head to Slitherine support at
support@slitherine.co.uk. You need to make a tour with them of your system configuration: Windows version, anti-virus used, anti malware used, video drivers, Windows UAC level and so on.