mesmo problema com você .. Dê uma olhada aqui
It's possible that the folder I copied was corrupted somehow. So, I just deleted it from my USB hard drive after doing a Drive Check (with only a File System Fix, from properties->tools the Drive Check button -- basically a checkdisk from explorer in Vista). I had also copied this folder to the Folder in Which MS keeps the backup sets. Anyway, after deleting it, I don't anymore get the error 'An internal error occured while enumerating backup sets'. Now I'm restoring from my USB external drive with no problem. Essentially, the reason this problem occurs suddenly is that something gets corrupted on the Drive you restore to from