Tweaking files in the Media.zip

I want to tweak the file lying_spruce in the Media.zip file. But everytime i copy it back to the zip folder after tweaking the game says "some files are missing" and wont start.

What do i wrong?

It's easier to create a folder named Media (and all needed sub folders) in the main game folder. Open the config.xml and copy " <MediaPath Path="Media" /> " before " <MediaPath Path="Media.zip" /> ".
Now you can copy files from media.zip to the media folder (it must be the same path as in media.zip!) and the game should load the tweaked files from the media.
Multiplayer and achievements will get disabled tho!
But you just have to temporary rename the media folder and you can play im MP.

Does i get it right.
Then i have the file double (once in zip once in "my media folder" but when i copy the Media Path on top in the config.xml the game will load that file at first?

Yes. I use this all the time, works perfectly. You can install mods or maps in the media folder too.