rf,
I also use a DIR-655 and have been suffering from a similar problem which I discussed in the 1.06 AV Issues post yesterday.
The cause of the problem was not the DIR-655. Based on the suggestion from someone else on the board, I reset the DNS-323 to Factory Default settings, and then re-enabled UPnP. After rebuilding the index all of my tracks (about 4,600) were displayed.
Prior to that the DNS-323 seemed able to share about a CDs worth of data, but nothing more.
Good luck.
M