title: Error empty response when logging in magento admin
body: <p>I really stuck on this issue, everytime i log in into magento admin, it's give me an <strong>ERR_EMPTY_RESPONSE</strong> on <em>google chrome</em> and <strong>Connection reset</strong> on <em>Mozilla</em>. </p>
  
  <p>The shop is still accessable, but it's load very slowly. It's working fine before, and suddenly become like this. </p>
  
  <p>I can't find a similiar issue like this, mostly are the shop that return an empty response and they still can access the admin page and it's caused of <strong><em>enabling flat category/products set up.</em></strong> </p>
  
  <p>I'm not sure if client enabling the <strong>flat category/products</strong>. If it so, what table should i edit using <em>phpmyadmin</em>? </p>
  
  <p>since i can't access the admin page, or there are another thing that cause this? <em>some error code, some files missing in admin directory or htaccess thing, actually i'm not doing changes on htaccess before</em>. Really need your help.</p>