Marvin,
I started having the same issue after moving to 10. No matter what I tried during the check out process ArcMap would completely shut down. I called ESRI and got Juan out of the Charlotte office. He had me create a folder on my C: drive and check out the data to it. It worked fine. Before, I had my data going to a folder, within a folder, within a folder, on the network. Hopefully this works for you.
Marti