Please see this FAQ link for WMP11 setup instructions this may help.
http://support.dlink.com/faq/view.asp?prod_id=2692&question=DSM-120%20/%20DSM-320%20/%20DSM-320RD%20/%20DSM-510%20/%20DSM-520%20/%20DSM-750
Step 1-2 done
Step 3 Your D-Link DSM-510 should now have a green check mark over it. Click the Apply button and then click the OK button.
DoneStep 4 Select which folders will be shared to your D-Link DSM-510. Select the down arrow under Library again. Next select the Add to Library option.
DoneStep 6 Windows® Media Player 11 will now scan the folders you have selected for supported media files.
Done (found 42 items more since the last scan)Step 7 Once your folders have been scanned and your media has been added to the Windows® Media Player 11 library you can select the Close option.
DoneStep 8 You can now return to your TV and select the Server option from the Home page of the D-Link DSM-510 or you can press the server button on the D-Link DSM-510 remote control.
Done but the WMP server is not listed (the LinksysWRT350N is and is functional with only a fraction is my files showing/scanned/playing)Step 9 Once you have confirmed that your Windows® Media Player sharing has been enabled and is showing on your D-Link DSM-510 you can select your Music, Photos or Videos options in the Home menu or press the hotkeys on your remote control.
Done-Not applicable per #8 notesVista help-Not ApplicableOther notes, the HP Laptop, D-Link DSM-510 and LinksysWRT350N are all on the same T100 wired network (192.168.1.103 .102 and .1 respectively) and are on the some subnet 255.255.255.0.
I can ping all 3 from the laptop.
XP Pro (sp2) has the firewall completely disabled.
The Anti-Virus is AVG 8.0.138 (latest available) has been disabled for this WMP 11 test.
Is it time for a RMA on the D-Link DSM-510