Downloads fail and keep failing with no error

I ran windows update today. The fist two updates went fine. The third hung
in the download stage for quite some time then finally just skipped to the
net update. From then on, none of the rest of the updates downloaded. I
rebooted and tried again.

Here's the current symptom. I select an update and the d/l status bar
starts near the completion of the file. It hangs for a long time them moves
on with a message that the update failed. Each update I select fails in this
way, but no error message is generated.

I've tried deleting the entire SoftwareDistribution folder and also trying
to regester the dll's the everyone always suggests registering.

I have Win XP SP2, and yes, it's a liget copy.