Warning: require_once(): Unable to allocate memory for pool. in /var/www/html/wordpress/piwik/core/Loader.php on line 71 (3 replies)

Was running fine until the following error.

There is an error. Please report the message (Piwik 1.11.1) and full backtrace in the Piwik forums (please do a Search first as it might have been reported already!).

Warning: require_once(): Unable to allocate memory for pool. in /var/www/html/wordpress/piwik/core/Loader.php on line 71

Backtrace -->

#0 Piwik_ErrorHandler(...) called at [/var/www/html/wordpress/piwik/core/Loader.php:71]
#1 Piwik_Loader::loadClass(...) called at [/var/www/html/wordpress/piwik/core/Loader.php:71]
#2 Piwik_Loader::loadClass(...) called at [/var/www/html/wordpress/piwik/core/Loader.php:108]
#3 Piwik_Loader::autoload(...) called at [:]
#4 spl_autoload_call(...) called at [/var/www/html/wordpress/piwik/core/ArchiveProcessing.php:241]
#5 Piwik_ArchiveProcessing::factory(...) called at [/var/www/html/wordpress/piwik/core/Archive/Single.php:211]
#6 Piwik_Archive_Single->prepareArchive(...) called at [/var/www/html/wordpress/piwik/core/Archive/Single.php:265]
#7 Piwik_Archive_Single->get(...) called at [/var/www/html/wordpress/piwik/core/Archive/Single.php:529]
#8 Piwik_Archive_Single->getDataTable(...) called at [/var/www/html/wordpress/piwik/core/Archive.php:368]
#9 Piwik_Archive::getDataTableFromArchive(...) called at [/var/www/html/wordpress/piwik/plugins/Referers/API.php:39]
#10 Piwik_Referers_API->getDataTable(...) called at [/var/www/html/wordpress/piwik/plugins/Referers/API.php:139]
#11 Piwik_Referers_API->getKeywords(...) called at [:]
#12 call_user_func_array(...) called at [/var/www/html/wordpress/piwik/core/API/Proxy.php:189]
#13 Piwik_API_Proxy->call(...) called at [/var/www/html/wordpress/piwik/core/API/Request.php:127]
#14 Piwik_API_Request->process(...) called at [/var/www/html/wordpress/piwik/core/ViewDataTable.php:431]
#15 Piwik_ViewDataTable->loadDataTableFromAPI(...) called at [/var/www/html/wordpress/piwik/core/ViewDataTable/HtmlTable.php:80]
#16 Piwik_ViewDataTable_HtmlTable->main(...) called at [/var/www/html/wordpress/piwik/core/Controller.php:151]
#17 Piwik_Controller->renderView(...) called at [/var/www/html/wordpress/piwik/plugins/Referers/Controller.php:254]
#18 Piwik_Referers_Controller->getKeywords(...) called at [:]
#19 call_user_func_array(...) called at [/var/www/html/wordpress/piwik/core/FrontController.php:136]
#20 Piwik_FrontController->dispatch(...) called at [/var/www/html/wordpress/piwik/index.php:52]