Attempt to set a non-property-list object as an NSUserDefaults

I thought I knew what was causing this error, but I can’t seem to figure out what I did wrong.

Here is the full error message I am getting:

Attempt to set a non-property-list object (
   "<BC_Person: 0x8f3c140>"
) as an NSUserDefaults value for key personDataArray

I have a Person class that I think is conforming to the NSCoding protocol, where I have both of these methods in my person class:

- (void)encodeWithCoder:(NSCoder *)coder {
    [coder encodeObject:self.personsName forKey:@"BCPersonsName"];
    [coder encodeObject:self.personsBills forKey:@"BCPersonsBillsArray"];
}

- (id)initWithCoder:(NSCoder *)coder {
    self = [super init];
    if (self) {
        self.personsName = [coder decodeObjectForKey:@"BCPersonsName"];
        self.personsBills = [coder decodeObjectForKey:@"BCPersonsBillsArray"];
    }
    return self;
}

At some point in the app, the NSString in the BC_PersonClass is set, and I have a DataSave class that I think is handling the encoding the properties in my BC_PersonClass.
Here is the code I am using from the DataSave class:

- (void)savePersonArrayData:(BC_Person *)personObject
{
   // NSLog(@"name of the person %@", personObject.personsName);

    [mutableDataArray addObject:personObject];

    // set the temp array to the mutableData array
    tempMuteArray = [NSMutableArray arrayWithArray:mutableDataArray];

    // save the person object as nsData
    NSData *personEncodedObject = [NSKeyedArchiver archivedDataWithRootObject:personObject];

    // first add the person object to the mutable array
    [tempMuteArray addObject:personEncodedObject];

    // NSLog(@"Objects in the array %lu", (unsigned long)mutableDataArray.count);

    // now we set that data array to the mutable array for saving
    dataArray = [[NSArray alloc] initWithArray:mutableDataArray];
    //dataArray = [NSArray arrayWithArray:mutableDataArray];

    // save the object to NS User Defaults
    NSUserDefaults *userData = [NSUserDefaults standardUserDefaults];
    [userData setObject:dataArray forKey:@"personDataArray"];
    [userData synchronize];
}

I hope this is enough code to give you an idea o what I am trying to do.
Again I know my problem lie with how I am encoding my properties in my BC_Person class, I just can’t seem to figure out what though I’m doing wrong.

Thanks for the help!