You can create a ‘support ticket’ on this Support site. I did that funnily enough, for the same thing you describe here! I received help, it was ‘advanced sharing’ on my pc that needed ‘password protection’ deselecting. So all fine, but then I encountered a further problem (I cannot now recall what it was, sorry) that meant I still could not see my files by going through that method where you are asked for your password.
But I have a reason for replying, as I found another, easier way to get WDTV to read my files. Here’s the workaround, you will still see all your files if you do it this way. On the home screen are 12 large coloured tiles, ‘ok’ (enter) the one that says ‘Videos.’ You will be offered 4 choices of places for WDTV to look for your files. (One is ‘Network Share,’ for example). It hardly matters if you don’t know which is the right choice - you can make the wrong choice, and the worst that will happen is that WDTV will say ‘no media present’ (or something like that). When you choose the right one (even if it takes your 4 guesses as to which is the right one to use) your files will appear, and thereafter will always be there unless you disconnect that source, ie., the pc is switched off - and even then, once you switch it on, your files will be seen on WDTV.
You can persevere with Community advice about the password problem, but that got me nowhere - there is conflicting advice, or advice that simply didn’t work for me, or try the (easier, I think) method I’ve described. If it works for you as it has for me, you’ll never have to bother about the password problem - it’s not involved, doing it this way.
One last thing, unconnected to the above. Somebody on here suggested choosing ‘list view’ for your files as it is more reliable as it uses far less memory.