Fix Wordpress errors caused by htaccess file

I installed the Leaf Wordpress template on my site which worked fine. Then I added a list of redirects to the .htaccess file. The intent was to redirect old static php pages to the new Wordpress category pages. This appears to have broken the Wordpress functionality. I do not know if the problem is in the .htaccess file or the back end (apache?). I do not want to rebuild the Wordpress categories and pages I've done (over 100 categories and 20+ posts). So reinstalling Wordpress or the Leaf theme is not an option (unless it is possible to export and re-import the existing work). The website is www.trackvids.com. Go to the main page and click the links -- you are sent to the [login to view URL] page I previously set up with the old site design or Wordpress generated pages that no longer work properly. WHAT I NEED FROM YOU: 1) A description of the actions you plan to take to resolve the issue (PLEASE TELL ME ALONG WITH YOUR BID) 2) Wordpress functionality restored with navigation links and page behavior working properly again.