after reading all of the posts here, most of the problems are the beta application can not get the show list from your one or more tivo device. The problem will be fixed in the later release. now for the beta2 version, there is a temporary workaround for you guys ( it works most of the time )
1 ,go to ~/Library/Preferences folder, trash or rename com.tivo.desktop.plist file, this will reset the settings of tivo transfer, won't do anything about your tivo files.
2, reopen the application, the preference window will pop up, asking for media access key, enter it. and you are ready to go.
now your tivo recordings should be seen.
if you still has no luck after steps above, please reply below.