[steve614]

My first thought...
Have you upgraded your Windows certificate for Tivo Desktop?

http://www.tivocommunity.com/tivo-vb/showthread.php?p=6166557#post6166557

 

[steve614]

Oh, OK.

I'm probably wrong, but doesn't Tivo Desktop have to be installed for TDN to work?
When you rebooted your Tivo, did you also reboot your computer and router?
Have you checked your IP addresses and such to see if they might have changed?
Have you had security/firewall software recently updated that might have changed a file transfer limit setting?

Just throwing out ideas for troubleshooting.