[quote:dm3r9qqj]They say an error window shows up saying DirectX8 is missing.
That's not right - the runtime uses DirectX 9. Microsoft release updates every few months to DirectX 9 without changing the version number from 9.0c. Construct uses the August 2008 update of DirectX, so you'll need that.
If you visit this page you'll see the exact error message they'll have received. Don't ignore it! It tells you exactly what is wrong, and how to fix it. If they follow the instructions, the game should then run.