I just heightmapped a small island. When I went to landscape it, I couldn't do anything. I would try raising and lowering the land, as well as adding terrain, and nothing worked. But, I was able to landscape the flat parts of the island that hadn't been changed by the heightmapper. Anyone know why landscaping isn't working?

If you're talking about the edges of the island (or spots nearby), this is because the CS doesn't like extremely steep slopes (roughly 3000 units between points) and will lock out alteration with anything but the smooth level tool if it gets to be too steep in any spot within the editor circle. If the slope is more than 4000 units between points, the whole cell will usually end up becoming permanently bugged.

On a side note, if you're working on an area smaller than 10x10 cells, you are best off using the landscape editor without ever touching the heightmap editor. This is because the heightmap ALWAYS generates a full 4 quads of that worldspace. What this means in the case of a small island is that you have several extra MB of file size which is being wasted. You might want to start over with the worldspace. If you find the landscape editor to be too slow when moving vertically, increase the landscape sensitivity multiplier under the editor options (same tab as the grid settings).

Well, the slope I had was very gentle. I don't know how many units it was, but it was more of a large mound than hill. About the height editing, I can't even use raise, lower, or smooth, or anything that edits height in the landscape editor. Also, I guess I was a little misleading about small island. My island goes from about 8, 13 to -2, -9 in a diagonalish shape.