Log in as root, assuming it is enabled. If it is not enabled you will need to do so. Off the top of my head, I can't remeber how to do so, I think it is in the NetInfo Utility, located in your utilities file.
If root is enable, you can drag and drop the folder into the trash, if you logged in using root. If you are using another user account, and do not want to log out, you can remove the folder and its contents using the terminal using the "sudo" or "su root" command.
From the command line type the following:
sudo rm -R /location of the folder/ (ie /Applications/app name or folder)
the terminal will ask for a password, type the root password
then go to the /Applications/ folder and type ls -a to see if the folder or app is gone. Or open the finder to see if the folder is gone.
Jason