[TYPO3] Istall Tool error

[Frederik Mortensen]

Im trying to upgrade from typo 3.7 to 3.8.1 (on my way to 4.0)

and cant get into the Install Tool because of this error;

TYPO3 Fatal Error: Extension key "sv" was NOT loaded!
(t3lib_extMgm::extPath)


Does it make sence, PLEASE help me if you know anything about this!!


Frederik