2.1 beta 1 -- Fatal error: Unable to find parent 'option category' with name 'filebase.file' for category with name 'filebase.file.supportThread'.

Fatal error: Unable to find parent 'option category' with name 'filebase.file' for category with name 'filebase.file.supportThread'.
Information:
id: 74c2e9d6854a10e9788b0bd59bf1429d7d1c5b9d
error message: Unable to find parent 'option category' with name 'filebase.file' for category with name 'filebase.file.supportThread'.
error code: 0
file: /home/sociall2/woltlabdev.com/wcf/lib/system/package/plugin/AbstractOptionPackageInstallationPlugin.class.php (138)
php version: 5.6.9
wcf version: 2.1.5 (Typhoon)
date: Mon, 06 Jul 2015 07:45:57 +0000
request: /acp/index.php?install-package/&&
referer: https://woltlabdev.com/acp/index.php?package-installation-confirm/&queueID=46&
Stacktrace:
#0 /home/sociall2/woltlabdev.com/wcf/lib/system/package/plugin/AbstractOptionPackageInstallationPlugin.class.php(32): wcf\system\package\plugin\AbstractOptionPackageInstallationPlugin->importCategories(Object(DOMXPath))
#1 /home/sociall2/woltlabdev.com/wcf/lib/system/package/PackageInstallationDispatcher.class.php(571): wcf\system\package\plugin\AbstractOptionPackageInstallationPlugin->install()
#2 /home/sociall2/woltlabdev.com/wcf/lib/system/package/PackageInstallationDispatcher.class.php(139): wcf\system\package\PackageInstallationDispatcher->executePIP(Array)
#3 /home/sociall2/woltlabdev.com/wcf/lib/acp/action/InstallPackageAction.class.php(73): wcf\system\package\PackageInstallationDispatcher->install('44793362')
#4 /home/sociall2/woltlabdev.com/wcf/lib/action/AbstractDialogAction.class.php(70): wcf\acp\action\InstallPackageAction->stepInstall()
#5 /home/sociall2/woltlabdev.com/wcf/lib/action/AbstractAction.class.php(49): wcf\action\AbstractDialogAction->execute()
#6 /home/sociall2/woltlabdev.com/wcf/lib/system/request/Request.class.php(58): wcf\action\AbstractAction->__run()
#7 /home/sociall2/woltlabdev.com/wcf/lib/system/request/RequestHandler.class.php(139): wcf\system\request\Request->execute()
#8 /home/sociall2/woltlabdev.com/acp/index.php(10): wcf\system\request\RequestHandler->handle('wbb', true)
#9 {main}