Happened randomly, and has no real impact except the annoying error popup - Lua pickup block - 2860

[Minerexstacy]

Summary: Not really sure what happened, but it seems like I was mining and the hearthlings were trying to pick up the drops (Happened 3 times)

Steps to reproduce:

1. ???

Expected Results: ???

Actual Results: ???

Notes: Started a brand new world, and first error I get after I cut down a tree, then start mining.

Attachments: http://pastebin.com/BWbdXfVB

Version Number and Mods in use: 2860

System Information: Intel i5, GeForce 520