Try Dice Player (Ads version). If your NAS supports FTP or SMB then combine with ES File Explorer to open the files.
Thanks. Its kind of weird to use two desperate Apps for it, bug it does work. Wish ES did NFS
It doesn't look like the toucpad is quite ready for HD playing off a NAS yet. I wonder if its a hardware issue or bandwidth issue. Need to copy one of the files to the TouchPad and see what happens locally.