Java Conflict? page wont display in IE7

hello. i am using an oscommerce modified theme. the [login to view URL] file has a custom (vista buttons) css menu with a linked .js file. [login to view URL] (works ok) once you click on a product... [login to view URL] (broken on I.E. 7) i think it conflicts with the lightbox installation i have on the [login to view URL] page. i want to keep the css menu i have. can anyone please help? needed asap. thanks