[TYPO3] can't add content

[Wail]

I upgraded from typo3 3.8.1 to 4.0.
Now I can't add any content to my page.

If I want to add a page, I get error "2: SQL error: 'Column 'media' 
cannot be null' (pages:NEW4456904932364)"

If I want to add a simple text pagecontent to one of the page, I get 
error "2: SQL error: 'Column 'l18n_diffsource' cannot be null' 
(tt_content:NEW4456914b57817)"

Please help.