If you are a fan of Japanese horror RPGs, you have almost certainly heard of Ao Oni (Blue Demon). Since its release in 2008, this game has terrified millions with its simple puzzle mechanics and the relentless, glitchy pursuit of the blue-skinned monster. However, for a significant number of players, the terror begins before the monster even appears—at the startup screen.

You double-click the Game.exe file. The window pops up. You see the title screen. Then, suddenly, a stark white dialog box appears with the cryptic message: "Script 'Game_Message' line 30: RuntimeError occurred."

This is the infamous "Ao Oni 30 Fix" —a search query that haunts forums like Reddit, Steam Community, and RPGMaker.net. Why is this error so common, and more importantly, how do you fix it permanently?

This article provides a definitive, step-by-step breakdown of the causes and solutions for the Ao Oni line 30 runtime error.

Provide a concise, step-by-step solution to clear the "30" puzzle/area and avoid the Oni, including key items, safe routes, and any timing tricks.

  • Use the acquired key on the locked chest/door immediately after finding it. If the chest contains a puzzle piece or lever, take it and return to the mechanism within the same route to avoid extra trips.
  • For timed lever puzzles: pull the first lever, then sprint to the second lever in the order shown by the clue you found earlier (if no clue, try clockwise). If you miss the window, retrace to the nearest safe room and wait for the Oni's patrol to pass, then retry.
  • If chased, use rooms with multiple exits and drop items (if possible) to slow the Oni. Avoid dead-end rooms unless you can lock the door behind you.
  • Once the mechanism unlocks (sound cue), open the newly available door and proceed to the next area. If a cutscene or encounter follows, be prepared to run immediately toward the pre-identified safe zone.
  • Save after clearing the area and before exploring new branching paths.

    • You are in the right place if you experience any of the following when launching Game.exe:

    If you are running Windows 10, Windows 11, or Windows 7 64-bit, you are almost guaranteed to encounter this error on your first launch.

    To fix the error, you must first understand what "Line 30" represents. Ao Oni was built using RPG Maker XP (or VX, depending on the translation). The "Game_Message" script controls text boxes and dialogue.

    In the original Japanese release, the game uses a specific font (usually MSGothic or UmePlus Gothic). Most Western PCs do not have this font installed. When the game reaches line 30 of the Game_Message script—the line that tells the computer to "draw the text using Font X"—the system panics. It cannot find the font, so it throws a RuntimeError.

    In short: The "Ao Oni 30 fix" is almost always a font issue.

    However, there are secondary causes, including:

    A surprising number of "line 30" errors are false positives. Modern anti-virus software (Windows Defender, McAfee, AVG) sometimes sandboxes the RGSS Player because it is an old executable.

    "Ao Oni" is a Japanese survival-horror puzzle game where a group of characters explore an abandoned mansion while hunted by a blue humanoid monster ("Oni"). The "30 Fix" refers to a common puzzle/area sequence involving a locked room and a 30-second or 30-step timing element that players must resolve to progress — often a fan term for a specific patched puzzle or walkthrough segment.