https://www.thezetateam.org/pxgame/arch ... %22DEMO%22
is the even older broken version. Without the hotfix/bugfix/re-release, the arena mode has no background image and is just black. Trying to play the arena on that version will crash the game after the first stage.
You can find posts/news about the bugfixed version by searching for "Project X: Love Potion Disaster 4.0 Bug Fixed and Comic" on Google.