new product or category or anything else - throws to login-page after save

[Daddy Chrome]

Hi 
i need your help.

Can't add new product or category (or anything else where you have to save the change).
i click Save button and go out to the joomla athorization page 
He added, but throws to login. and again and again. Let Thunder Strike Me 
I can not understand. maybe you have some ideas?
I think it's the security settings

latest Joomla 2.5.6
latest VM 2.0.10

Sorry for my strange english 
Thank you!

[Daddy Chrome]

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