I got this error while trying to do an automatic update
There is an error. Please report the message (Piwik 1.12) and full backtrace in the Piwik forums (please do a Search first as it might have been reported already!).
Warning: unlink(/home/chiles/public_html/piwik/tmp/assets/asset_manager_global_css.css) [function.unlink]: No such file or directory in /home/chiles/public_html/piwik/core/AssetManager.php on line 378
Backtrace -->
#0 Piwik_ErrorHandler(…) called at [:]
#1 unlink(…) called at [/home/chiles/public_html/piwik/core/AssetManager.php:378]
#2 Piwik_AssetManager::removeMergedAsset(…) called at [/home/chiles/public_html/piwik/core/AssetManager.php:396]
#3 Piwik_AssetManager::removeMergedAssets(…) called at [/home/chiles/public_html/piwik/core/Piwik.php:132]
#4 Piwik::deleteAllCacheOnUpdate(…) called at [/home/chiles/public_html/piwik/plugins/CoreUpdater/CoreUpdater.php:62]
#5 Piwik_CoreUpdater->dispatch(…) called at [:]
#6 call_user_func_array(…) called at [/home/chiles/public_html/piwik/libs/Event/Dispatcher.php:284]
#7 Event_Dispatcher->postNotification(…) called at [/home/chiles/public_html/piwik/core/PluginsManager.php:674]
#8 Piwik_PostEvent(…) called at [/home/chiles/public_html/piwik/core/FrontController.php:272]
#9 Piwik_FrontController->init(…) called at [/home/chiles/public_html/piwik/index.php:46]
Fatal error: Call to undefined function Exception() in /home/chiles/public_html/piwik/core/AssetManager.php on line 379