You must update your load-balancing configuration. See DefaultSettings.php entry for $wgDBservers.
<p>Backtrace:</p>
<ul>
<li>GlobalFunctions.php line 450 calls wfBacktrace()</li>
<li>LoadBalancer.php line 418 calls wfDebugDieBacktrace()</li>
<li>LoadBalancer.php line 379 calls LoadBalancer::reallyOpenConnection()</li>
<li>LoadBalancer.php line 361 calls LoadBalancer::openConnection()</li>
<li>DatabaseFunctions.php line 52 calls LoadBalancer::getConnection()</li>
<li>SpecialTimeline.php line 54 calls wfGetDB()</li>
<li>SpecialPage.php line 265 calls SpecialPage_Timeline::execute()</li>
<li>index.php line 143 calls SpecialPage::executePath()</li>
</ul>