I'm receiving a very similar error. The strange thing is that samba used to be installed a few weeks ago (I successfully transferred some files from my laptop) and when I tried to use it today, it wasn't working.. it wasn't even installed! I went to Synaptic and when I tried to install samba (3.0.7-1ubuntu6) I got this error:
EDIT: I just noticed that I didn't originally install samba, it was smbclient. Now I can't remove samba (same error as jak is getting)..
Setting up samba (3.0.7-1ubuntu6) ...
update-rc.d: warning: /etc/rc2.d/S91samba is not a link to ../init.d/samba
update-rc.d: warning: /etc/rc3.d/S91samba is not a link to ../init.d/samba
invoke-rc.d: dangling symlink: /etc/rc2.d/S91samba
dpkg: error processing samba (--configure):
subprocess post-installation script returned error exit status 102