Class is not key value coding-compliant

I know the meaning of this error, but I'm really struggling with it, and I need someone's help :

2010-09-21 15:03:11.562 Stocks[5605:207] *** Terminating app due to uncaught 
exception 'NSUnknownKeyException', reason: '[<NSObject 0x499fb20> 
setValue:forUndefinedKey:]: this class is not key value coding-compliant 
for the key actionText.'

There is my code here :

AlertCell.h

#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>


@interface AlertCell : UITableViewCell {
    IBOutlet UILabel *actionText;
}

@property (retain, nonatomic) UILabel *actionText;

@end

And

AlertCell.m

@implementation AlertCell
@synthesize actionText;
   
- (void)dealloc {
    [actionText release];
    [super dealloc];
}
   
@end

The problem happens just there :

- (UITableViewCell *)tableView:(UITableView *)tableView 
         cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    static NSString *CellIdentifier = @"Cell";
    
    AlertCell *cell = 
      (AlertCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    
    if (cell == nil) {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"AlertCell" 
                                                         owner:nil 
                                                       options:nil];
        for (id oneObject in nib) {
            if ([oneObject isKindOfClass:[UITableViewCell class]]) {
                cell = (AlertCell *)oneObject;
                break;
            }
        }
    }    
    
    
    cell.actionText.text = [arrayAlert objectAtIndex:indexPath.row];
    return cell;
}

On this line :

NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"AlertCell" 
                                             owner:nil 
                                           options:nil];

As asked, here is my header for the TableViewCOntroller :

#import <UIKit/UIKit.h>


@interface AlertesViewController : UITableViewController {
    NSMutableArray *arrayAlert;
}

And you can see my XIB file (as XML): http://pastebin.com/FDVzLYZu

@end

Can anyone help me ? Thanks a lot !