1) Check to make sure you have credit for the herb mastery puzzle.
2) Check to make sure you have Exploration 2 technology done.
3) Check to make sure the scientist trying to make cutting tools is a master scientist.

If you have done both of the above and still you do not see a cauldron in the wood pile I am stumped. Have you done any time traveling? I have read in another thread about a missing gong puzzle piece that time traveling can have unexpected results. Perhaps time traveling affects this puzzle as well.

Let us know what happens!
- Borg