Svn update fails (0.5)

I made a svn update to version 0.5. When I open piwik in the browser I get the following error message:

Invalid argument supplied for foreach() 
in '<path>/piwik/core/Config.php' at the line 248

#0  Piwik_ErrorHandler(2, Invalid argument supplied for foreach(), <path>/piwik/core/Config.php, 248, Array ([allSections] => Array ())) called at [<path>/piwik/core/Config.php:248]
#1  Piwik_Config->cacheConfigArray() called at [<path>/piwik/core/Config.php:292]
#2  Piwik_Config->__get(Plugins) called at [<path>/piwik/core/FrontController.php:209]
#3  Piwik_FrontController->init() called at [<path>/piwik/index.php:99]

Any ideas?

A complete new install solved my problem.