I found a solution; If anybody can't move any files to trash make this;
Run Disk Utility -> Repair Disk Permissions
Then try this method I found online.
1. Reboot the computer.
2. Login with the troubled user account
3. Open 'Terminal'
4. Type:
sudo rm -frv ~/.Trash
Note: This removes the old ".Trash" directory and all files and folders in it.
3. Type:
mkdir -v ~/.Trash
Note: This creates a new ".Trash" directory in your home folder.
4. Type:
killall Finder
Note: This kills/restarts Finder
5. Close Terminal.
6. Reboot Computer. Log in as the 'hopefully fixed' user.
See if the trash works now.