Saves from older versions (e.g., 0.4.x) might not be compatible with 0.5.4. It is usually recommended to start a new game to see all new content and avoid script crashes.
This site frequently hosts Visual Novel Walkthroughs for similar titles. File: TheSinger-VER_0.5.4-pc.zip ...
Double-click The Singer.exe (or similar .exe file) to start. Saves from older versions (e