TYPO3 Core

i have a local typo3 trunk and i have used it for a long time. i just pull new changes via git and now i get the following error when calling the backend:

#1270853879: TYPO3 Fatal Error: Extension key "t_y_p_o3.c_m_s.lang" is NOT loaded!

Backtrace:

7 TYPO3\CMS\Core\Extension\ExtensionManager::extRelPath("t_y_p_o3.c_m_s.lang")
6 TYPO3\CMS\Extbase\Utility\ExtensionUtility::registerModule("TYPO3.CMS.lang", "tools", "language", "after:extensionmanager", array, array)
5 require("C:\xampp\htdocs\typo3v4core\htdocs\typo3\sysext\lang\ext_tables.php")
4 TYPO3\CMS\Core\Extension\ExtensionManager::loadSingleExtTablesFiles()
3 TYPO3\CMS\Core\Extension\ExtensionManager::loadExtTables(boolean)
2 TYPO3\CMS\Core\Core\Bootstrap::loadExtensionTables(boolean)
1 require("C:\[...]\htdocs\typo3\init.php")

i then tried to call the install tool directly which works and go through the upgrade wizard but there i get a crash as well on the first step:

Install Outsourced System Extensions
[func] 
[about] 
[cshmanual] 
[feedit] 
[opendocs] 

Class tx_em_Connection_ExtDirectServer does not exist

Guys, this does not look like a "stable" core that can be deployed...