While you can lay timber flooring over tiles, there are some things to consider before doing this.
1. If the original layer of tiles come loose, this can potentially damage your new flooring.
2. Tiles are rarely laid perfectly flat, meaning there could be some hollow areas.
3. Glue can become loose over time between tile and timber. To avoid this, clean your tiles with methylated spirits and lightly sand back to ensure the glue can bond.