DMA's Holiday tilesets have no traps nor water.
If you load a level with that original DMA tileset, the program is correct to flag traps and waters as errors.
I haven't looked at the file, thus I can't guess how it was created. Maybe people eventually put the Snow tileset's traps and water into a customized Holiday tileset. You'll likely need to know exactly which Holiday tileset the level author had in mind.
-- Simon
Thank you for the info, I did never notice there was no traps in Holiday Lemmings. I was making a Christmas level by myself, via the old NeoLemmix Editor 1.43, and Vanilla Lemmix throw me that error.
That mentioned editor allowed me to use traps and water and everything else, and at validating the level, everything was fine. I was able to play it in CustLemmix, so I expected Vanilla Lemmix allow me to play it, too.
Instead of my former level, I attached one made with random objects, in order to show that everything but traps and water was ok.
In case you wonder, I am using the old editor and the old players because I've always wanted to make a levelpack with the original 8 skills, and for the original engine, before moving to the new NeoLemmix Editor and its new skills and terrains. Although I'll release the levelpack also for NeoLemmix 12.X.X.
One last question: all things considered, it is not O.K. that the old NeoLemmix editor for Lemmix allow making Xmas levels with traps?