I have the same problem with the *8015 error.
One site said to clear this folder C:\Windows\SoftwareDistribution after shutting off Windows update service and clearing the folder and turning update back on. It seems to have gotten rid of the error message but now update in Win 7 only looks for windows updates and not all Microsoft updates.
This error also may have fouled up the restore function on a 32bit Home machine and a 64bit laptop too!