Are the files supported files as per the manual? If you're just using Windows 7, you might try downloading the latest version of the PC Share networking software from the website to see if refreshing those folders gives you more consistent stability in populating those files.
I've been trying to share music, videos and photos from my main Windows 7 PC with my Samsung (UE46B7020WWXXU) TV. The result is a bit hit and miss and only some folders appear. I'm using a Samsung WISO9ABGN wireless LAN adaptor through a Sitecom Mimo-XR wireless router. Can you help?