I have it working now (hopefully all the way...). I thought I'd post what I did in case others had the same problem. store_id needed to be added to the products table. Here is the code that I used:
ALTER TABLE `products` ADD `store_id` INT( 11 ) DEFAULT '0' NOT NULL ;
I haven't gotten this far yet, but I think I will need to delete and re-add all of the sample data because they won't have store_id populated. I remember when I added it originally, that it griped at me about too many columns -- I'm guessing this is the reason. That last "1" is there for store_id.