Linksys Wireless Router :: Can't Access Network Shares With E3000

I replaced my old Linksys WRT54G wireless router with the new E3000 wireless router. The installation was a breeze, but not what followed henceforth. I was able to access the internet on my wireless desktop/laptop/Netflix ROKU player/WD TV live media player, but lost access to all the network shares. I spent a lot of useless time with Linksys chat support and phone support, where they said their responsibility is only getting the internet working. They said they are not responsible for file and printer sharing issues, and suggested I use a third-party paid support package to resolve my issues. Over and above spending a hefty amount for the lates top of the line E3000 router, I was not going to shell out additional money for support.
 
Thinking that it could probably be due to some Windows XP firewall/anti-virus (McAfee) issues, I disconnected the E3000 and connected the old WRT54G back again. Lo and behold, everything started working fine again. I could access the shared folders of my desktop (to which my router is attached) and printer, from the wireless laptop/desktop/media player just as before without any problems. I then switched back to the E3000 and lost the shares again. So I have come to the conclusion, there is definitely some setting within the E3000 that is preventing the file and printer sharing. I just can't figure out what it could be, and am at a point of returning it back to the store as defective. The extra N-speed is useless to me if my devices can't access the network shared content.Also, I tried to set up the UPnP media server feature of the E3000 by attaching USB storage and configuring it via the Linksys web based utility, but my media player is unable to access the content.