Fehler beim Update von WBB 4.0.11 zu 4.1.5

Fatal error: Could not execute prepared statement: SQLSTATE[HY000]: General error: 1025 Error on rename of './exo_wbb/wcf1_moderation_queue' to './exo_wbb/#sql2-1ec9-f5f3a5' (errno: 152)
Information:
id: 394d2e1b7e0a8d1567e754b763a781a2e77a7ed3
error message: Could not execute prepared statement: SQLSTATE[HY000]: General error: 1025 Error on rename of './exo_wbb/wcf1_moderation_queue' to './exo_wbb/#sql2-1ec9-f5f3a5' (errno: 152)
error code: 0
sql type: wcf\system\database\MySQLDatabase
sql error: Error on rename of './exo_wbb/wcf1_moderation_queue' to './exo_wbb/#sql2-1ec9-f5f3a5' (errno: 152)
sql error number: HY000
sql version: 5.5.41-0+wheezy1
sql query: ALTER TABLE wcf1_moderation_queue DROP FOREIGN KEY `079f01974702ea08981c7d50a2d59313_fk`
file: /var/www/forum/wcf/lib/system/database/statement/PreparedStatement.class.php (97)
php version: 5.4.36-0+deb7u3
wcf version: 2.1.5 (Typhoon)
date: Wed, 22 Jul 2015 07:38:05 +0000
request: /acp/index.php/InstallPackage/?&
referer: http://forum.exo-reallife.de/acp/index.php/PackageUpdate/?
Stacktrace:
#0 /var/www/forum/wcf/lib/system/database/editor/MySQLDatabaseEditor.class.php(189): wcf\system\database\statement\PreparedStatement->execute()
#1 /var/www/forum/wcf/lib/system/database/util/SQLParser.class.php(298): wcf\system\database\editor\MySQLDatabaseEditor->dropForeignKey('wcf1_moderation...', '079f01974702ea0...')
#2 /var/www/forum/wcf/lib/system/package/PackageInstallationSQLParser.class.php(402): wcf\system\database\util\SQLParser->executeDropForeignKeyStatement('wcf1_moderation...', '079f01974702ea0...')
#3 /var/www/forum/wcf/lib/system/database/util/SQLParser.class.php(168): wcf\system\package\PackageInstallationSQLParser->executeDropForeignKeyStatement('wcf1_moderation...', '079f01974702ea0...')
#4 /var/www/forum/wcf/lib/system/database/util/SQLParser.class.php(49): wcf\system\database\util\SQLParser->executeStatement('ALTER TABLE', 'ALTER TABLE wcf...')
#5 /var/www/forum/wcf/lib/system/package/plugin/SQLPackageInstallationPlugin.class.php(78): wcf\system\database\util\SQLParser->execute()
#6 /var/www/forum/wcf/lib/system/package/plugin/AbstractPackageInstallationPlugin.class.php(72): wcf\system\package\plugin\SQLPackageInstallationPlugin->install()
#7 /var/www/forum/wcf/lib/system/package/PackageInstallationDispatcher.class.php(571): wcf\system\package\plugin\AbstractPackageInstallationPlugin->update()
#8 /var/www/forum/wcf/lib/system/package/PackageInstallationDispatcher.class.php(139): wcf\system\package\PackageInstallationDispatcher->executePIP(Array)
#9 /var/www/forum/wcf/lib/acp/action/InstallPackageAction.class.php(73): wcf\system\package\PackageInstallationDispatcher->install('92f1425c')
#10 /var/www/forum/wcf/lib/action/AbstractDialogAction.class.php(70): wcf\acp\action\InstallPackageAction->stepInstall()
#11 /var/www/forum/wcf/lib/action/AbstractAction.class.php(49): wcf\action\AbstractDialogAction->execute()
#12 /var/www/forum/wcf/lib/system/request/Request.class.php(58): wcf\action\AbstractAction->__run()
#13 /var/www/forum/wcf/lib/system/request/RequestHandler.class.php(139): wcf\system\request\Request->execute()
#14 /var/www/forum/acp/index.php(10): wcf\system\request\RequestHandler->handle('wbb', true)
#15 {main}