[Plugin: Local Market Explorer] All of a sudden I’m getting a 500 Internal Server Error

Up until yesterday, the plugin worked fine on my site. Today, I’m getting the #500 error.
Examples: http://60646blog.com/local/60646/ or http://60646blog.com/local/60630/
Would anyone have an idea which direction I should be looking for a solution? My hosting provider suggests changing permissions on the htaccess file which I did, but no joy.

http://wordpress.org/extend/plugins/local-market-explorer/