Multisite crashed after update to 4.0 – please help

Hi,
Next day after updating my multisite WP to 4.0 I found that lot of plugins don’t work and when I tried to edit a page/post there are 11 same line messages on the top:
“Warning: Invalid argument supplied for foreach() in /home/*my-accaunt*/public_html/wp-includes/media.php on line 2690”

Multisite control dashboard disappeared.
There is no plugins menu in dashboard (so I can’t istall new one, deactivate etc). Also I tried to open the /plugin-install.php but it said, “You do not have sufficient permissions to install plugins on this site.”
There is no themes in menu for activation (so I can not activate/install etc).
I’m administrator but I have no more access to edit users I can only remove them.

What I did:

I tried to deactivate plugins by renaming – didn’t help
I tried to copy media.php from previous versions – didn’t help.
I deleted all themes except the Fourteen – there were same problems but one of my “multisites” (/ru) doesn’t work after this experiment – just blank screen. I deleted Fourteen theme and uploaded previous but it thinks that Fourteen theme still there. So Russian part of site crashed at the end.

P.S. Among plugin User Access Manager and S2member also don’t work so commerciall and private information became open to public! It is really disaster! Of course I manually set all pages which are not public into “private” or draft.

My site: here

Additional info
when I tried to do backup I received this:
Error getting table details: wp_sitemeta
Error getting table details: wp_sitemeta
(I have normal backup which I did before update to 4.0)

Please help!