Gettin Bad Access while adding Annotations - ios

Question

I´m trying to to add many Annotations (depends on how many objects a have in my Array) to my Mapview like this:
-(void)viewWillAppear:(BOOL)animated
{
[mapView removeAnnotations:mapView.annotations];
for (Daten *info in datenArray) {
CLLocationCoordinate2D location;
location.latitude = (double)[info.lati doubleValue];
location.longitude = (double)[info.longi doubleValue];
MapPin *newAnnotation =[[[MapPin alloc] initWithTitle:info.rating andCoordinate:location] autorelease];
[mapView addAnnotation:newAnnotation];
}
[self zoomToFitMapAnnotations:self.mapView];
[self.mapView selectAnnotation:self.mapView.annotations.lastObject animated:YES];
}
The first time I switch to that View it works perfectly...But if i come a second time to this View, i get this Bad Access with Error:
*** -[CFString length]: message sent to deallocated instance 0x17e140c0
Edit:
Thats my MapPin Class:
#interface MapPin : NSObject <MKAnnotation> {
NSString *title;
NSString *subtitle;
CLLocationCoordinate2D coordinate;
}
#property (nonatomic, copy) NSString *title;
#property (nonatomic, readonly) CLLocationCoordinate2D coordinate;
#property (nonatomic, readonly, copy) NSString *subtitle;
- (id)initWithTitle:(NSString *)ttl andCoordinate:(CLLocationCoordinate2D)c2d;
EDIT2:
Edit3:
Here´s the implementation:
#import "MapPin.h"
#implementation MapPin
#synthesize title, coordinate, subtitle;
- (id)initWithTitle:(NSString *)ttl andCoordinate:(CLLocationCoordinate2D)c2d {
[super init];
subtitle = ttl;
title = #"Rating:";
coordinate = c2d;
return self;
}
- (void)dealloc {
[title release];
[subtitle release];
[super dealloc];
}
#end

Answer 1

You should send retain or copy message for object in init.
if (self = [super init]) {
subtitle = [ttl copy];
title = [#"Rating:" retain]
...
}
return self;
#"Rating:" is equal method which create autoreleased object.
Or you can use self.title = #"Rating:";.