I'm looking into this to see what the issue could be.
This week I purchased a P4600. I hooked it up to my network (wired) and to my LCD TV (HDMI). Upon startup, it asked me to upgrade the firmware, which I did.
I went to add my shared folder on my windows 7 machine but I cannot. It finds my computer but when I put in my username/password it says it is not correct. I even put in the computername\username and password and that did not work either.
So I tried the manual way and that did not work either. I have followed the guides on the internet and can't seem to get it to work.
I even created a new user account to make sure it wasn't my user/pass --- username was user, and password was pass. I gave that user account the correct permissions, and still no go.
This seems to be a known issue -- is there ANY way for me to get a shared folder from windows 7 onto the P4600 over a wired network?