thx man this workedFor me, I fixed by:
1) Turn the user experimental feature on in tmodloader the game, under Settings > tModLoader Setting > User Experimental Feature.
2) Create a new folder name "TexturePacks" Under Documents > My Games > Terraria > ModLoader.
3) Lastly, move the texture pack zip file to the folder and rename it as "TexturePack" (no space, and make sure its file type is zip)
4) Reopen the game and it should work.