Thanks for helping test this everybody, here's what I found:
efranlje - It does seem to be working... it shows 3 friends, and since the 4th friend doesn't have a location listed, it's correctly not showing them. It also centers the map over efranlje's location. So that's working.
LASSIE - It's not working for you because you don't have a location set for yourself. So the map is getting confused when it attempts to center the map.
Karl - I can't see what's happening, since you removed the widget.
Based on this, we have a couple small bugs to fix.
1) Make it do something logical when the current blog's user doesn't have a location set. (Lassie's will start to work after that).
2) Add a user configurable "zoom". Since as efranlje points out, you might want to start zoomed out.
3) Make it support the proper size window area depending on the theme.