Possibly. How have you configured the IP address for your MBL? Static or Dynamic? If you have configured a static IP for your NAS? If so then is the Gateway set to the same IP address as your router? If not then set it to that.
Also, if the DNS is not set, set it to Google’s public DNS IP address which is: 8.8.8.8
( http://code.google.com/speed/public-dns/ )
If you have the IP set dynamically then it’s a puzzle why your MBL can’t get out to the Internet.
