What Version of NeoTech are you using: NeoTech-1.9-3.0.3.jar, Bookshelf API 1.9-3.0.2 and Forge 1813

If possible, did you break and replace the block: crash at startup

Please Pastebin.com the crash Report and put link here: http://pastebin.com/raw/JE8wVZ8A

This seems to occur when Tinker's Construct is enabled. NeoTech works fine when Tinkers is disabled and Tinkers works fine when NeoTech is disabled, but when to together, boom.

same issue, same versions as well... maybe item id's are over lapping?

same here.
i did notice this during the load cycle. it was all the molten_*
[
Dangerous alternative prefix tconstruct for name molten_copper, invalid registry invocation/invalid name?

Dangerous alternative prefix neotech for name molten_copper, invalid registry invocation/invalid name?
]

No I missed a null check. It has been fixed with the latest build on Jenkins