I'm assuming that the uninitialized data is being permanently saved by Fieldrunners to some preference file on first run? If so, then perhaps simply attempting to reinstall multiple times may get the map working for some, without having to go through the whole "restart iPhone" process? I'm assuming, of course, that uninstalling Fieldrunners clears out all of its preference files as well, giving it a slight chance of making the map finally show up.
Would love to know exactly what uninitialized data causes the map to not show up at all though as it doesn't sound like the game would need some specifically initialized variable to display the default enabled map.
Sorry, my technical side is getting overly curious at 5:37am local time.

