Excuse me, spurius characters had been inserted: the call stack was:
Response was '<br />
<font size='1'><table class='xdebug-error xe-fatal-error' dir='ltr' border='1' cellspacing='0' cellpadding='1'>
<tr><th align='left' bgcolor='#f57900' colspan="5"><span style='background-color: #cc0000; color: #fce94f; font-size: x-large;'>( ! )</span> Fatal error: Allowed memory size of 4294967296 bytes exhausted (tried to allocate 72 bytes) in /var/wwwc/piwik/core/DataTable.php on line <i>1317</i></th></tr>
<tr><th align='left' bgcolor='#e9b96e' colspan='5'>Call Stack</th></tr>
<tr><th align='center' bgcolor='#eeeeec'>#</th><th align='left' bgcolor='#eeeeec'>Time</th><th align='left' bgcolor='#eeeeec'>Memory</th><th align='left' bgcolor='#eeeeec'>Function</th><th align='left' bgcolor='#eeeeec'>Location</th></tr>
<tr><td bgcolor='#eeeeec' align='center'>1</td><td bgcolor='#eeeeec' align='center'>0.0000</td><td bgcolor='#eeeeec' align='right'>226272</td><td bgcolor='#eeeeec'>{main}( )</td><td title='/var/wwwc/piwik/index.php' bgcolor='#eeeeec'>../index.php<b>:</b>0</td></tr>
<tr><td bgcolor='#eeeeec' align='center'>2</td><td bgcolor='#eeeeec' align='center'>0.0471</td><td bgcolor='#eeeeec' align='right'>2795216</td><td bgcolor='#eeeeec'>Piwik\FrontController->dispatch( )</td><td title='/var/wwwc/piwik/index.php' bgcolor='#eeeeec'>../index.php<b>:</b>71</td></tr>
<tr><td bgcolor='#eeeeec' align='center'>3</td><td bgcolor='#eeeeec' align='center'>0.0515</td><td bgcolor='#eeeeec' align='right'>3032656</td><td bgcolor='#eeeeec'><a href='http://www.php.net/call_user_func_array' target='_new'>call_user_func_array</a>
( )</td><td title='/var/wwwc/piwik/core/FrontController.php' bgcolor='#eeeeec'>../FrontController.php<b>:</b>117</td></tr>
<tr><td bgcolor='#eeeeec' align='center'>4</td><td bgcolor='#eeeeec' align='center'>0.0515</td><td bgcolor='#eeeeec' align='right'>3032824</td><td bgcolor='#eeeeec'>Piwik\Plugins\API\Controller->index( )</td><td title='/var/wwwc/piwik/core/FrontController.php' bgcolor='#eeeeec'>../FrontController.php<b>:</b>117</td></tr>
<tr><td bgcolor='#eeeeec' align='center'>5</td><td bgcolor='#eeeeec' align='center'>0.0522</td><td bgcolor='#eeeeec' align='right'>3036408</td><td bgcolor='#eeeeec'>Piwik\API\Request->process( )</td><td title='/var/wwwc/piwik/plugins/API/Controller.php' bgcolor='#eeeeec'>../Controller.php<b>:</b>34</td></tr>
<tr><td bgcolor='#eeeeec' align='center'>6</td><td bgcolor='#eeeeec' align='center'>0.0536</td><td bgcolor='#eeeeec' align='right'>3061776</td><td bgcolor='#eeeeec'>Piwik\API\Proxy->call( )</td><td title='/var/wwwc/piwik/core/API/Request.php' bgcolor='#eeeeec'>../Request.php<b>:</b>220</td></tr>
<tr><td bgcolor='#eeeeec' align='center'>7</td><td bgcolor='#eeeeec' align='center'>0.0738</td><td bgcolor='#eeeeec' align='right'>3137696</td><td bgcolor='#eeeeec'><a href='http://www.php.net/call_user_func_array' target='_new'>call_user_func_array</a>
( )</td><td title='/var/wwwc/piwik/core/API/Proxy.php' bgcolor='#eeeeec'>../Proxy.php<b>:</b>212</td></tr>
<tr><td bgcolor='#eeeeec' align='center'>8</td><td bgcolor='#eeeeec' align='center'>0.0738</td><td bgcolor='#eeeeec' align='right'>3138312</td><td bgcolor='#eeeeec'>Piwik\Plugins\VisitsSummary\API->getVisits( )</td><td title='/var/wwwc/piwik/core/API/Proxy.php' bgcolor='#eeeeec'>../Proxy.php<b>:</b>212</td></tr>
<tr><td bgcolor='#eeeeec' align='center'>9</td><td bgcolor='#eeeeec' align='center'>0.0738</td><td bgcolor='#eeeeec' align='right'>3138424</td><td bgcolor='#eeeeec'>Piwik\Plugins\VisitsSummary\API->getNumeric( )</td><td title='/var/wwwc/piwik/plugins/VisitsSummary/API.php' bgcolor='#eeeeec'>../API.php<b>:</b>118</td></tr>
<tr><td bgcolor='#eeeeec' align='center'>10</td><td bgcolor='#eeeeec' align='center'>0.1097</td><td bgcolor='#eeeeec' align='right'>3940008</td><td>