I am using magento default product import functionality under sytem>import/export>import

When i upload the file and click on check data button the the page calls ajax and a error is returned 

```
Fatal error: Call to a member function getName() on a non-object in /var/www/html/app/code/core/Mage/ImportExport/Model/Import/Entity/Product.php on line 390

```

I didn't have any customization in core files.

What i have done : 
1) I have replaced the whole ImportExport module with a fresh one
2) I have also found some similar problems and done as their solution was saying there may be indexing issue so i have truncate all the flat tables and re-index all

Thanks