This could be the old XP DMA issue. If so, research XP DMA RESET and do that.
Also, I use WinDV for such transfers as other methods seemed to not work as well.
I have trouble transfering my old Hi8 Digital tape to my computer for editing. I use a firewire and it works fine but every 3 or 4 minutes the computer stops the upload for a few seconds. I assume the computer is transfering the data from RAM to the harddrive. The final movie is horrible to watch as it pauses every few minutes.