I know it's been over a year since your post, but I just installed joodatabase this week and had the exact same problem! Everytime I try to bring up a single entry, I get one big 404 error! I figured there's no way we could be the only two, so once I found a solution (to mine at least) I should post a reply in case there are others.
Like yourself, category view was working flawlessly, data wildcards were perfect.
However, it turns out that the id was not quite so perfect. Or at least not as perfect as joodb wanted it. The id I was using are our product codes -- all unique, the field was defined as the key, indexed.
The problem? My product codes didn't start with a number. The instant I added a number to the front of the product code, the instant it worked. (I feel very stupid to have taken almost 5 hours to figure that out!)
To save myself some time, I found it was just easier to drop the primary key from my product codes, and create a new auto-increment field defined as the key and then use that as the id.
Hope this helps you too!
