Go to the main menu option, mod tab, then hit the "Show Mod Path" button. This will show you the location of your mod folder, which should be in the same directory as your settings folder, even if it is in an unusual location.
You may then want to make sure the folders in that directory and settings files are not set to read only.
If you registered your game with Stardock, you can download the latest patched version from the Stardock store.