I have not been able to recreate the problem when using a wired network. It does appear to have something to do with the wireless.
I will try v11 and see if the is any better with the wireless. It is just a matter of time before the dog eats the cat5 draped through the house, so wired is not really an option.
UPDATE: After I put the 802.11g adapter back, I noticed something. At the beginning of a song that is about to err, the play bar on the Tivo stays at 0 for some seconds, then pauses that number of seconds prior to the end of the song. For example, a 5 minute song stayed at 0 for 3 seconds, then stopped at 4:57. It stayed here for about 30 seconds then timed out.
I presume that there is some mis-match between how long Tivo thinks a song has been playing and how long it actually has been playing. Your software probably provided the entire song after some delay ( for whatever reason: network, software, etc.), but the Tivo thinks the server should be giving it the other X seconds. When some timeout period elapses, the Tivo thinks there is a network or server problem and give the generic error I have been seeing.
Of course I could be wrong...
Going to try V11 beta. Will let you know if it works more consistently.
UPDATE 2:
OK, I tried v11, with the same results. However, I also tried TiVo Desktop, which has exactly the same problem. I am going to refer this to TiVo for them to look into since this is obviously an issue with the TiVo itself. Thanks for your suggestions.