In short, YOU caused the world to crash.
Even though the Universal Minecraft Editor is the easiest, fastest, and most reliable Minecraft world data editor, it does not always protect you from yourself.
The Universal Minecraft Editor can be compared to a word processor like Notepad or Microsoft Word. These programs let you write and edit anything you want, including typos. You can create amazing, beautiful essays and letters with Microsoft Word, but you can also create "asdjkbghbgsghjbasegrhjaegr." And while features like auto-correct can help you make less mistakes, the end product is still up to you.
The Universal Minecraft Editor has groundbreaking new features like quick mods and error checking to try to limit the mistakes people make. But like auto-correct, it doesn't pick up everything and it won't turn "asdjkbghbgsghjbasegrhjaegr" into the next Stephen King novel.
So what can you do? You can simply undo the mods you did. Go back through your previous steps and track down where your typo is. I know this is easier said than done, but I have NEVER come across a crashing world that couldn't be repaired.
With that being said, I too am not immune to typos. If you catch a bug with the Universal Minecraft Editor, submit a ticket and I will gladly look into it!