...and Windows XP. I try to connect to my empeg over usb...

As was stated elsewhere in this thread, there is a known bug with USB and Windows XP. The work-around is to use ethernet.

...(only one ethernet card and it's in use)...

Then I get the feeling that this ethernet card is connected to another device directly instead of into a hub? The solution is to get a hub, the whole point of ethernet is to connect a whole bunch of devices to the same network. Hubs are quite cheap these days.

after it gets done uploading the mp3s and moves on to rebooting the player, 75% of the time, it doesn't reboot and emplode gets an error. if i manually cycle it and run the sync again it finishes up fine

This is a known bug in the current beta software. It will be fixed in the next beta. When you switch to ethernet, this specific bug will not go away and you will still need to sometimes manually cycle the power on the player at that stage of the synch. However, your other bugs should go away when you switch to ethernet. Let us know how it goes. And by the way, ethernet troubleshooting tips can be found in the "home connections and networking" section of the FAQ.