Memory leak when using TBXML in Objective-C

I'm new to Objective C and am still not very clear about how to use retain and release. In the following code, I want to use TBXML to parse an XML file and populate a TableView. The code works, but when I "Analyze" my app, Xcode says there are memory leaks in the variable name. I suppose I should release the variable after retaining it, however, whenever I tried to release it, no matter where I do it, it always produced an error. I also tried NOT to retain it, but it also produced an error.

Can somebody please explain what is happening here?

- (void)loadNews {

    TBXML * tbxml = [[TBXML tbxmlWithURL:[NSURL URLWithString:@"http://www.abc/def.xml"]] retain];

    // If TBXML found a root node, process element and iterate all children
    if (tbxml.rootXMLElement) {

        TBXMLElement *categoryElement = [TBXML childElementNamed:@"category" parentElement:[tbxml rootXMLElement]];

        do {
            NSString *name = [TBXML valueOfAttributeNamed:@"name" forElement:categoryElement];
            [name retain]; // Something wrong with this line?

            NewsCategory *newsCategory = [[NewsCategory alloc] initWithCategoryName:name];

            // get entries in the category
            TBXMLElement *entryElement = [TBXML childElement开发者_运维百科Named:@"entry" parentElement: categoryElement];

            do {
                NSString *title = [TBXML textForElement:[TBXML childElementNamed:@"title" parentElement:entryElement]];
                NSString * icon = [TBXML textForElement:[TBXML childElementNamed:@"icon" parentElement:entryElement]];
                NSString * link = [TBXML textForElement:[TBXML childElementNamed:@"link" parentElement:entryElement]];
                NSString * desc = [TBXML textForElement:[TBXML childElementNamed:@"desc" parentElement:entryElement]];

                NewsEntry *newsEntry = [[NewsEntry alloc] init];
                newsEntry.title = title;
                newsEntry.icon = icon;
                newsEntry.link = link;
                newsEntry.desc = desc;

                [newsCategory addEntry:newsEntry];

                [newsEntry release];
            } while((entryElement = entryElement->nextSibling));


            // save category
            [newsData addCategory:newsCategory];

            [newsCategory release];


        } while((categoryElement = categoryElement->nextSibling));


    }

    // release resources
    [tbxml release];


    [newsTableView reloadData];
}

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If the guys who created [TBXML valueOfAttributeNamed: forElement:] followed the naming convention the value should be autoreleased. You do not need to retain it.

However, you need to retain or copy it in the [NewsCategory initWithCategoryName:] metod.