I can not connect to a password protected share from my Mac

The next problem I am having is that after converting from Share to User mode, I cannot connect to any shares from the PC. Ironically, I can connect via the Mac. The entire reason I migrated from Share to User security mode was because I could not connect from a Mac, but I could connect from a PC.

The error I get is:
"my-nas" is not set up to establish a connection on port "File and printer sharing (SMB)" with this computer.

I looked up that error message in these forums, and the only hit I got was this:
http://www.readynas.com/forum/viewtopic.php?f=65&t=41583&p=231438&hilit=+not+set+up+to+establish+a+connection+on+port+SMB#p231438

Which doesn't really apply to my situation.

First, I don't see how a user can make a mistake by creating a share name that is the same as a user name. When I accidentally attempted to do this, I was prevented from creating the user. Second, I am not setting up a system from scratch. I am following the instructions posted here on how to migrate from the old, unsupported Share security mode to the supported User security mode.

So, I have 3 shares:
media
richard
tracey

I have 3 users:
thp (in group rt)
rtp (in group rt)
guest (which I did not configure. It should have come set up already).
Both thp and rtp have a password associated with the user.

I have 1 group:
rt
thp and rtp have their primary group set to rt

media should be RW by group rt, and R by nogroup
the other shares should be RW by group rt and have no permissions for nogroup

I cannot connect from the PC to any share, regardless of whether it is public/guest accessible or not. I don't think this is a user/permissions configuration error.

Any ideas/documentation I could try?

I *really* just want to be able to connect to this device using either a PC or a Mac, and have some shares password protected. This certainly must be possible.