[Beta4]Hangup

I had just checked my city, built a hut, intended to move my units on the map (3d shown).

Game window goes black. Game doesn't answer. Memory used nearing 948 464k, using 25% cpu (looks like 1 of the 4 cores at 100%).

Had to terminate process by hand. No crash dump or info available.

There's a boatload of files in the Impulsereactor directory (I certainly hope this will no longer be the case after beta, I don't want Impulsereactor or any MP things to run or do anything while I'm playing), but no usable data.

I reloaded the last savegame to try and reproduce but was unable to.