Correct / modify PHP search engine

I am looking for someone to correct / modify the attached search engine, results page or pagination files as I am encountering problems with the pagination.

When a user enters a keyword in the search engine it is meant to check a SQL database for a match in ten possible columns and then displays the results on a results page if there is a match. If there is no match then a custom error message is displayed saying no results have been found. The search engine appears to work fine when you show ten results per page but to test it out I have been limiting the number of results per page to two but the pagination script appears to fail as the second page displays the custom error message to say that there are no matches when I know there are.

You can check it out by visiting www.hacti.com and using the product search box (second box down) and using the keyword ‘Vitamins’ to see the results page and the error when trying to view page 2