There are currently some issues on cloud checklists. The app don't crash, but it's rather some synchronization problems (e.g. deleted item coming back).
I'm working to improve this feature and fix there issues at the same time. Also, I'll remove some limitations on cloud checklists (e.g. not being able to sort the items). I expect to release an update this summer.
While I speak about cloud checklists, I wanted to highlight that this feature is available only with Android 2.2 and above... Android 2.1 users still have the previous version (4.11). I'm not sure if I'll be able to fix that, but I'll think about it when I have released the new version of Checklist.