I like Doggcatcher when it works, but I have found it to be one of the most unreliable applications I have ever used on any platforms. At best, only 1-2% of download attempts actually work. Most downloads get between 30-50% done and then they fail consistently.
It doesn't matter whether I use Wi-Fi or 3g. The app does not download Buzz Out Loud or Windows Weekly, both of which are on Doggcatchers list of Top Feeds.
This is on a stock Motorola Droid on Verizon running 2.0.1.
The downloading logic in DC rarely has problems of its own but it possible, so please send the log (in the menu) and I'll take a look. Most of the time there are IO problems on the phone either reading from the network or writing to the SD card.