Ok so I think I've figured out the samba problem. I have a linux server with all my media files (video in various formats etc). I've used mediatomb to serve this over uPnP for my PS3 because PS3 sucks in terms of reading more than 1 video codec type. I know that boxee does'nt like my transcoded upnp streams and thus doesn't play them.
Someone on the forum had suggested that I use samba instead as boxee can play mkv natively without the need of transcoding unlike my ps3. So I've finally gotten around to this and now I've exported my shares via samba.
I can see the video files when I browse via boxee in FILES and try to play the example video file (mkv ogg + something or other). It freezes boxee completely.
I removed this source (smb://blah blah) and did it another way.
On the boxee machine itself (windows box) I just mapped a network drive like I would normally, and added a LOCAL SOURCE to boxee which represented the same location.
Loaded the same exact mkv file and it loaded perfectly.
Verdict: Locally loaded samba shares work. Remotely loaded via boxee smb:// shares fail badly. And freeze boxee.
Just wanted to share my experience and see what others might think.