Hiya.

Yes, Yahoo! does index and rank .asp pages (and .php pages). We rank #1 or #2 for many of our main terms on both Y! and Google with .asp pages.

Edited to add:
Having said that, most of our pages, although .asp are not database generated. They are built from includes, but we don't serve them on-the-fly from content in a DB like a CMS would. That means we don't have long URLs with extra parameters after the .asp extension. Some engines don't really like those long dynamic URLs. Could that be affecting your site?