The following savegame  http://dl.dropbox.com/u/5057853/pb_city/jmf41.EleSav display some nice problems with city building:

In all the 4 cities I own (2 level 4, 1 level 3 and 1 level 2), I am currently unable  to build houses outside the 8 blocks of 4 tiles  surrounding the center of my town. I was able to do it 2 times before as displayed by the cities.

When modard have raised to level 3, I was able to build a mine on the tile 3 block away from the center. Sadly, the game crashed and when I reloaded the savegame, I am no longer able to build that mine, even if my city is level 3.

I have no idea why I can't build on some empty tiles: they aren't swamp, montain or coast. Dirie is a good show case: I have nine tiles available form my city level but I have no tile available when I want to build something.