That's cause you're still running 3.05!
Scroll up and you'll see I pushed an update (3.06)
New update:
V 3.07
Hopefully the script will no longer try to use methods which do not exist
Improved rock crab refreshing system
If trying to hop worlds but under attack, instead of waiting, script now runs as if it would refresh the crabs, then switches worlds, then runs back.
Updated NPC definitions