There was a bug where choosing to replay a domino set could sometimes cause a crash. This happened most frequently in the Patio Puzzle level. To get the fix, all you have to do is go to your Windows Start menu, then to Programs => Gamieon => Dominoze Demo, and run the "Check for Updates" feature to download the latest Dominoze files. The updater will do the rest of the work.
There are some other crashes under investigation which are harder to figure out; including one when saving or loading a domino set after prolonged game play. We will keep on it until it's fixed. In the meantime, if Dominoze or the Editor ever crash, and you get the prompt to send the error message to Gamieon, please do so and help us wipe out those bugs!