Objective C iPhone SBJson parser memory leek when data is loaded the second time

I have a problem in my iPhone application. I'm loading points into a Google map. These points are generated from a remote JSON file. Data is loaded without problems the first time I start the application but when I select a row in the pickerview and want to change the active pins after the program is startet i get a lot of memory leeks and the program also crashes if i continue doing it. It happens when i execute this method:
[self loadMainData:@"http://mysite.com/json.php"];

I don't know why this command works the first time i load the application when the viewDidLoad method is executed but not anymore. I guess i need to empty the arrays or release the data or something? I'm hoping you experts have an idea what needs to be done and how to do it.

#import "MapperViewController.h"
#import "MyAnnotation.h"
#import "JSON.h"

@implementation MapperViewController

@synthesize mapView, btnFilter, btnRoute;

-(void) viewDidLoad
{
    [super viewDidLoad];
	
	pickerViewArray = [[NSMutableArray alloc] init];
	
	[self loadMainData:@"http://mysite.com/json.php"];
}

-(void) getJsonData: (NSString*)JsonURL
{
	//Define raw JSON string
	NSString *MyRawJson = [[NSString alloc] initWithContentsOfURL:[NSURL URLWithString: JsonURL]];
	
	if ([MyRawJson length] == 0) //If string doesn't contain any value
	{
		return; //Stop execution
	}
	
	SBJSON *parser = [[SBJSON alloc] init]; //Create parser
	list = [[parser objectWithString:MyRawJson error:nil] copy]; //Parse string
	
	[parser release];
	[MyRawJson release];
}

-(void) loadMainData: (NSString*)JsonURL
{
	[self getJsonData: JsonURL]; //Load JSON data using a method
	
	array0 = [list objectAtIndex:0]; //Define array0
	array1 = [list objectAtIndex:1]; //Define array1
	array2 = [list objectAtIndex:2]; //Define array2
	
	[mapView setDelegate:self];
	
	for(int i = 0; i < [array1 count]; i++)
	{
		//Add data to the picker view
		[pickerViewArray addObject:[array1 objectAtIndex:i]];
	}
	
    //[mapView setMapType:MKMapTypeStandard];
	[mapView setMapType:MKMapTypeHybrid];
    [mapView setZoomEnabled:YES];
    [mapView setScrollEnabled:YES];
	
    MKCoordinateRegion region = { {0.0, 0.0 }, { 0.0, 0.0 } };
	
	MyAnnotation *ann;
	
	//Get the number of pins
	int numberOfPins = [[array0 objectAtIndex:0] intValue];
	int numberOfCols = 4;
	int numberValue = 0;
	
	//Make loop to place pins
	for (int i = 0; i <= numberOfPins; i++)
	{
		if (i != 0)
		{
			ann = [[MyAnnotation alloc] init];
			
			numberValue = (numberOfCols * (i-1));
			
			region.center.latitude = [[array0 objectAtIndex:numberValue+1] floatValue]; //41.902245099708516;
			region.center.longitude = [[array0 objectAtIndex:numberValue+2] floatValue]; //12.457906007766724;
			ann.title = [NSString stringWithFormat:@"%@", [array0 objectAtIndex:numberValue+3]]; //@"Test title1";
			ann.subtitle = [NSString stringWithFormat:@"%@", [array0 objectAtIndex:numberValue+4]]; //@"Test subtitle1";
			
			[mapView setShowsUserLocation:NO];
			
			ann.coordinate = region.center;
			[mapView addAnnotation:ann];
			
			[ann release];
		}
	}
	
	region.center.latitude = 48.200001; 
	region.center.longitude = 12.300000; 
	region.span.longitudeDelta = 0.7f; 
	region.span.latitudeDelta = 0.7f;  
	[mapView setRegion:region animated:YES];
}

- (NSString *)pickerView:(UIPickerView *)thePickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component //This method asks for what the title or label of each row will be.
{
	return [pickerViewArray objectAtIndex:row]; //We will set a new row for every string used in the array.
}

- (void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component //And now the final part of the UIPickerView, what happens when a row is selected.
{
	/* Remove points from map start */
	NSArray *existingpoints = mapView.annotations;
	if ([existingpoints count] > 0)
	[mapView removeAnnotations:existingpoints];
	/* Remove points from map end */

	if (row != 0)
	{
		//Reload points using the selected values
		[self loadMainData:[NSString stringWithFormat:@"http://mysite.com/json.php?category_id=%i", [[array2 objectAtIndex:row] intValue]]];
	}
	else
	{
		//Reload points using the selected values
		[self loadMainData:@"http://mysite.com/json.php"];
	}
}

Select allOpen in new window