Ohh, I'm very sorry if my plugin destroyed your world. I hope you had an backup or undo worked :p
I will update to 7.3. For your issue I don't know how to reproduce it, so it's currently hard to say why the plugin didn't work =(
Edit: You found a bug, it's because you had a selection between the coordinate corners. I'll fix this!
Don't worry it was a test server for a mod + spawn building site Let's hope you fix the bug, can't wait to be able to copy and paste the spawn structure so I can wipe my main server