iPhone MKMapView : the map can’t load completely

I don't know what's make wrong, my map can load, but the image on the map is not completely load. plx help. thz a lot. Here is the simulate map from the iPhone开发者_如何学运维: (Added more example image.)

http://img689.imageshack.us/img689/8476/screenshot20100309at841.jpg alt text http://e.imagehost.org/0508/Screen_shot_2010-03-09_at_8_58_12_PM.jpg

Here is the code:

MKCoordinateRegion theRegion;
MKCoordinateSpan theSpan;
theSpan.latitudeDelta = 0.005;
theSpan.longitudeDelta = 0.005;

theRegion.center =  manager.location.coordinate;
theRegion.span = theSpan;

myMap.scrollEnabled = YES; 
myMap.zoomEnabled = YES; 

[myMap setRegion:theRegion];
[myMap regionThatFits:theRegion];

Don't you do anything in the main thread that would prevent the map tiles to load fully ?

Solved with SDK updated.