Now that I'm home and can see the image, I don't think that's the issue. Those are the A tiles - the autotiles.
So ... check the map settings and make sure you have the correct tileset selected.
Check the tileset in the Tilesets tab and make sure you have the A slots filled. The missing ones would be specifically in the A2 slot.
Check the image and make sure it's a .png image (not .PNG and not .jpg or .JPG or any other variation).
Make sure the image is 768x576 pixels exactly (I don't think this is the issue though).
If all of those things look okay, can you please provide the following screenshots
- another from within the editor, but this time showing the full editor screen and not just the map. Make sure you have this map selected, and the A tab on the tile palette is showing
- a screenshot of the map properties window (which you can get by clicking on the map name and pressing space)
- a screenshot of the tileset tab, with this tileset selected, and the A tab showing
@BikeHelmet your issue is not the same. You should open a new thread for your issue. When you do, please fix the image. It shows for me as a long, incredibly narrow line which I have to zoom in to click on, then open in another window.