I can reproduce the problem when the N900 is mounted via USB, therefore I guess it is related to one of the base tiles not being available. Couldn't reproduce it on the Desktop yet though with a similar setup, so I need to debug it further on the device. I'll release a new version once I found and fixed the problem.

While we're at it, can someone with a working Marble 1.4.0-1 confirm that the height profile info box does work now? Create a route, click somewhere in the map and choose info boxes => elevation profile in the menu.