Out of scope error when adding an object to an NSMutableArray

I am trying to add a class object to an NSMutableArray but the object appears to be out of scope after adding it.

interface:

#import <Cocoa/Cocoa.h>

@class Person;

@interface MyDocument : NSDocument
 {
    NSMutableArray *employees;
    IBOutlet NSTableView *raiseTableView;
 }

- (IBAction)createEmployee:(id)sender;
- (IBAction)deleteSelectedEmployees:(id)sender;
@end

Part of the .m file:

#import "MyDocument.h"
#import "Person.h"
@implementation MyDocument


- (id)init
{
    self = [super init];
    if (self) {
        employees = [[[NSMutableArray alloc] init]retain];
    }
    return self;
}


- (IBAction)createEmployee:(id)sender
{
    Person *newEmployee = [[Person alloc] init];
    [employees addObject:newEmployee];
    NSLog(@"personName is: %@, expectedRaise is: %f", newEmployee.personName, newEmployee.expectedRaise);
    [newEmployee release];
    [raiseTableView reloadData];
}

The NSLog prints everything correctly. When I look at employees it shows 1 object added, when I look at the object it has a notation that it is out of scope and when I try to print it I get null for a result. Consequently, when it tries to reloadData things blow up. Anyone give me a hint as to what I am forgetting? Thanks.

TableView code:

#pragma mark Table view datasource methods

- (NSInteger)numberOfRowsInTableView:(NSTableView *)tempTableView
{
    return [employees count];
}

- (id)tableView:(NSTableView *)tempTableView objectValueForTableColumn:(NSTableColumn *)tempTableColumn row:(NSInteger)rowIndex
{
    // What is the identifier for the column?
    NSString *tempIdentifier = [tempTableColumn identifier];

    // What person?
    Person *tempPerson = [employees objectAtIndex:rowIndex];

    // What is the value of the attribute named identifier?
    return [tempPerson valueForKey:tempIdentifier];
}

- (void)tableView:(NSTableView *)tempTableView setObjectValue:(id)anObject forTableColumn:(NSTableColumn *)tempTableColumn row:(NSInteger)rowIndex
{
    NSString *tempIdentifier = [tempTableColumn identifier];
    Person *tempPerson = [employees objectAtIndex:rowIndex];

    // Set the value for the attribute named identifier
    [tempPerson setValue:anObject forKey:tempIdentifier];
}