UIPickerView NSUnknownKeyException

I've seen a lot of similar questions but none of them solve my problem or made the solution clear to me. I've a made a nib file with a UIPickerView.
When I run the application I get this error.

Terminating app due to uncaught exception 'NSUnknownKeyException',
 reason: '[<UIApplication 0x68633e0> setValue:forUndefinedKey:]:
 this class is not key value coding-compliant for the key pickerview.'
 

My ViewController.h

#import <UIKit/UIKit.h>
 #define CATEGORY 0
 #define VALUES 1
 
 @interface ViewController : UIViewController <UIPickerViewDelegate , UIPickerViewDataSource> {
     NSDictionary* dictionary;
     NSArray *keys,*values;
     IBOutlet UIPickerView *pickerview;
 }
 @property (retain,nonatomic) NSArray *keys, *values;
 @property (retain,nonatomic) NSDictionary *dictionary;
 @property (retain,nonatomic) UIPickerView *pickerview;
 @end
 

My ViewController.m

#import "ViewController.h"
 
 @implementation ViewController
 @synthesize keys,values,dictionary;
 @synthesize pickerview;
 
 -(void)dealloc {
     [keys release];
     [values release];
     [dictionary release];
     [pickerview release];
     [super dealloc];
 }
 
 - (void)didReceiveMemoryWarning
 {
     [super didReceiveMemoryWarning];
 }
 
 #pragma mark - View lifecycle
 - (void)viewDidLoad
 {
     NSBundle* bundle = [NSBundle mainBundle];
     NSString* str = [bundle pathForResource:@"testlist" ofType:@"plist"];
     NSDictionary* tempd = [[NSDictionary alloc] initWithContentsOfFile:str];
     self.dictionary = tempd;
     [tempd release];
     self.keys = [dictionary allKeys];
     self.values = [dictionary objectForKey: [keys objectAtIndex:0]];
    [super viewDidLoad];
 }
 
 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
     return 2;
 }
 
 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
     if (component == CATEGORY) {
         return keys.count;
     }
     return values.count;
 }
 
 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
     if (component == CATEGORY) {
         NSArray* tvalues = [dictionary objectForKey:[keys objectAtIndex:row]];
         self.values = tvalues;
         [pickerview selectRow:0 inComponent:VALUES animated:YES];//Xreiazetai?
         [pickerview reloadComponent:VALUES];
     }
 }
 
 - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
     if (component == CATEGORY) {
         return [keys objectAtIndex:row];
     }
     return [values objectAtIndex:row];
 }
 
 - (void)viewDidUnload
 {
     [super viewDidUnload];
 }
 
 - (void)viewWillAppear:(BOOL)animated
 {
     [super viewWillAppear:animated];
 }
 
 - (void)viewDidAppear:(BOOL)animated
 {
     [super viewDidAppear:animated];
 }
 
 - (void)viewWillDisappear:(BOOL)animated
 {
     [super viewWillDisappear:animated];
 }
 
 - (void)viewDidDisappear:(BOOL)animated
 {
     [super viewDidDisappear:animated];
 }
 
 - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
 {
     return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
 }
 
 @end
 

I made sure that dataSource , delegate outlets of the Picker are pointing to the File's Owner as also the picker view referencing outlet.

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