can't see how to link download to attribute, and Fatal error in store

[ChristopherMexico]

Joomla 1.5 RC2,  virtuemart 1.1  nightly build from yesterday.

I set up the store, tried to add a category and product.  I can't see how to link the downloadable file to the file type attributes that I had added either.
I setup a link in the joomla menu to the store and then I see the sample products and my product.

When I click on a product I get the following error

Fatal error: Call to a member function addItem() on a non-object in /home/plseduca/public_html/storysofa/ebook-store/libraries/joomla/application/application.php on line 793