I'm upgrading from 2.2 to 2.3 but the page "freeze" during step 2 - "system checking" with the yellow bar near the left side of the entire bar. I tried so view the "page source", the result is:
 </td> 
	  <td class="main"> 
	    <div id="MainPageStatus_statusBlock"> 
	      <p> 
		<h3> <span id="MainPageStatus_title"> </span> </h3> 
	      </p> 
 
	      <p> 
		<h4><span id="MainPageStatus_description"> </span></h4> 
	      </p> 
 
	    <table id="statusTable" cellspacing="0"> 
		<tr> 
		  <td id="MainPageStatus_progressMade" class="progressMade"> </td> 
		  <td id="MainPageStatus_progressToGo" class="progressToGo"> </td> 
		</tr> 
	    </table> 
	    </div> 
 
	    <script type="text/javascript"> 
	      // 
and nothing else...