How to open the finder as root
I fully accept the warnings other people have given here regarding running finder as root... but in a limited scenario it is very useful.

The OP had a problem using the: 


  sudo /System/Library/CoreServices/Finder.app/Contents/MacOS/Finder


I suspect he/she may have also been using something like TotalFinder or XtraFinder

If so, then use the options in the custom menu for these add-ons to restart Finder.

Alternatively: 


Run the command above (sudo Finder) in terminal
You will notice the hard drive icon overlayed on your desktop for root... but it is probably not clickable (hence the error message)
Then open a new tab in Terminal (so the sudo tab is still running) and kill the standard Finder (without using Sudo)   "killall Finder"
You should now be able to double click on the overlayed HardDrive desktop icon, or...
In the same non-Sudo tab of Terminal, just type "open ."


One other point to note... if you're wanting to browse as root, you probably also want to see hidden files. So before starting all this, type the command below into Terminal. This is a permanent setting, so you only need to do it once for the root user.


  sudo defaults write com.apple.finder AppleShowAllFiles TRUE