We are facing below error after login to the admin panel.
I guess your magento instance got compromised.
There is no
local.php file in the skin folder.
And all the
evals in the error message point to the same thing.
You should delete the
local.php file from the
skin folder and look in your code for something that is calling that file.
You can even take a clean version that you are using (from here) and compare it with your instance to see what files may be modified.