Need help getting the WP_Query loop working with pagination

Here’s my problem: If you go to this site, http://www.usedboatmall.com, you will see a custom search widget in the sidebar. The search works properly on the first page, but once you go the next page it does not pass the custom search query along.

For example, if you search for Bass Boat you get 14 results (as of this morning). The first 10 results are displayed on the first page. If you click to page 2 it shows 0 results.

Any help is much appreciated!