when you mounted the Public folder, what user name did you specify? Since you can connect, it seems you just have credentials issues. Now, these credentials are the ones for MBL, NOT for the Mac.
you would probably have to unmount and mount it again. It will also only show the shares available to the user/credentials you enter.
It will also depend how far in you went in the path:
//192.168.1.50/Public vs //192.168.1.50/
http://osxdaily.com/2010/09/20/map-a-network-drive-on-a-mac/