You should be able to do the following:
Right click the folder and select get info, or click on it and select the same option from the file menu. Then, at the bottom there will be something that says, Ownership & Permissions: You can... "No Access." Below that is a part you can expand. You should be able to expand that, click on the lock next to the first item, and change the ownership. Then you can also make it so that others besides the owner have permissions, if you wish (the next two boxes).
If this doesn't work, it is definitely also doable from the command line via something like...
cd /users/shared
sudo chown -R system:admin *
sudo chmod -R 666 *
...