Smarty tries to open templates_c files which don't exist

I got there errors, then I tried to upgrade to 4.5 (thought they maybe are fixed in that version, but the errors are now the only thing I see on the upgrade page (?q=civicrm/upgrade&reset=1)

Warning: include(/var/www/crm/sites/default/files/civicrm/templates_c/en_US/de_DE//%%29/29F/29F525FB%%localization.js.tpl.php): failed to open stream: No such file or directory in Smarty::fetch() (line 1264 of /var/www/crm/sites/all/modules/civicrm/packages/Smarty/Smarty.class.php).
Warning: include(): Failed opening '/var/www/crm/sites/default/files/civicrm/templates_c/en_US/de_DE//%%29/29F/29F525FB%%localization.js.tpl.php' for inclusion (include_path='/var/www/crm/sites/default/files/civicrm/customphp/:.:/var/www/crm/sites/all/modules/civicrm:/var/www/crm/sites/all/modules/civicrm/packages:.:/var/www/crm/sites/all/modules/civicrm:/var/www/crm/sites/all/modules/civicrm/packages:.:/usr/share/php:/usr/share/pear') in Smarty::fetch() (line 1264 of /var/www/crm/sites/all/modules/civicrm/packages/Smarty/Smarty.class.php).
Warning: include(/var/www/crm/sites/default/files/civicrm/templates_c/en_US/de_DE//%%4A/4AC/4ACAAD27%%success.tpl.php): failed to open stream: No such file or directory in Smarty::fetch() (line 1264 of /var/www/crm/sites/all/modules/civicrm/packages/Smarty/Smarty.class.php).
Warning: include(): Failed opening '/var/www/crm/sites/default/files/civicrm/templates_c/en_US/de_DE//%%4A/4AC/4ACAAD27%%success.tpl.php' for inclusion (include_path='/var/www/crm/sites/default/files/civicrm/customphp/:.:/var/www/crm/sites/all/modules/civicrm:/var/www/crm/sites/all/modules/civicrm/packages:.:/var/www/crm/sites/all/modules/civicrm:/var/www/crm/sites/all/modules/civicrm/packages:.:/usr/share/php:/usr/share/pear') in Smarty::fetch() (line 1264 of /var/www/crm/sites/all/modules/civicrm/packages/Smarty/Smarty.class.php).

I tried to delete everything in the templates_c directory, but some directories are in use, so they can't be deleted