Henk,
Something is amiss with your scenery elevation. The land behind those docks is elevated and in your screenshot, it's not. Also, I think you're missing an object on that dock to the right. If I'm not mistaken.
These things need further attention. Check out the scenery object tester and make sure all of the objects are showing for you. Look at the top of our scenery page to find the tester, install it and take a look. Please report back what you find. It looks to me like you're missing the CeyX libraries.
On the lack of proper elevation that you're showing, go into your settings and verify what your Scenery Mesh Resolution settings are at. Should be at 5
Brad