Says the game is damaged and asks me to put it in the paper bin...

tried to redownload and reinstall..

running the latest version of mac OSX..

There is a Troubleshooting FAQ, Click on the game in your library, then click on "support". You should check it out, as it has more things to check than I have pasted below.

Here is one part of the troubleshooting FAQ: (*I have never had this problem, so I have never tried this solution*)

Game "is damaged and can't be opened. You should move it to the Trash."
a) Redownload the game using the newest version of the GOG Downloader:
https://secure.gog.com/downloader
To download, make sure the "GOG.com Downloader mode" is switched to ON before clicking the "Game installer" button. After the download is complete, reinstall the game.
b) Use this workaround if using the Download didn't help:
- Go to Applications -> Terminal
- Type in:
xattr -d com.apple.quarantine
but don't press Enter.
- Drag the application to the Terminal window, this should add the path.
- Press Enter.