I'm not sure when the problem started and I haven't found many others who are having a similar issue. I only noticed it because the maps in profiles in the Twitter for BB app weren't working. I tried removing Twitter for BB but that didn't have any effect.
I see a "S Java Exception - OutofMemoryError" in the event log if I run bbmaps. There's a thread in the GPS & Mapping forum - Blackberry maps - No map displayed
where at least one other person is having issues with the maps not displaying.