[TYPO3] new site - BE empty main frame

[Katja Lampela]

Hi all,

I installed a dummy site 4.0.3, created then one page and now upgraded 
to 4.0.4. After upgrading I can't add or edit anything because the main 
frame in the right is empty every time I click on something, like New 
page inside, or edit icon of a be user or page properties.

I've done db comparing and updating of reference index - and I've 
upgraded tens of sites now and never experienced this.

Anyone experienced this one or any pointers where to go? Thanks!

Katja