FYI. I ran into this problem when I replaced a bunch 15-20 of icons (png) files in /usr/share/icons/hicolor/64x64/hildon with some slightly (5-8k) larger ones. and then added shortcuts to them on a homepage.. The problem only went away when I compressed the PNG files.

I believe there is a very very low memory limit for hildon-desktop which can be reached by
- replacing icons with larger ones
- installing many new apps and then adding shortcuts to them one home pages