EntityMalformedException: Missing bundle property on entity of type file.

I installed the Media Gallery and its dependent modules.

I created a new content item of type "Gallery", set the title and saved.
On the page itself, I hit the Add Media button to which I added 7 images and proceeded to upload them.
They displayed as expected, but I was not happy with the title for each image, so I edited the first image and changed its title only. When I clicked on the "Save" button, I got the following message.

Notice: Undefined index: file in media_edit_submit() (line 366 of C:\xampp\htdocs\mysite\sites\all\modules\media\includes\media.pages.inc).
EntityMalformedException: Missing bundle property on entity of type file. in entity_extract_ids() (line 7562 of C:\xampp\htdocs\mysite\includes\common.inc).

I am using Drupal v7.16
I am using the latest versions of all dependent modules. Althought I should list them, there isn't really a clean way to do so. If you can suggest something, please do let me know.