When my page load go to the bottom of the blog why?

Hi friend im new and this is my first post in this forum, well, i really need help from you, the problem is that my forum when i open it in firefox when it gets load go to the bottom of the page i dont know why but this hapent when i did the upgrade to the new version 2.6.3, i have tryed to desative all the plugins and the error follow.

Help please.