Well, I decided to make this tutorial for blocklanders who have problems.
1st. Tell the problem in the Subject.
2nd. Post your console.log by following these steps: Run blockland, do the thing that crashes it, close blockland, and post the log.
3rd. Wait for answers, and if nothing helps, delete your recently downloaded add-ons.
[NOTE: Im not sure if tutorials are allowed, but if not, delete this.]