Photoshop Elements :: Organizer Failed During Folder / File Move

I have a large image collection, in excess of 40,000.  I'm running on a PC with Windows 7 and all updates installed.  I just purchased PSE 11 to replace PSE 10. After installing PSE 11 I converted my catalog.  That seemed to go OK.  At that point I discovered that my C: drive was almost full so I decided to move my image collection from its C: drive location to an external hard drive that had sufficient capacity.  In order to ensure the integrity of the catalog I decided that I should use the PSE 11 Organizer to move the files.  This would allow the Organizer to update the location information for the files as it moved them, although it was clear that this would take many hours to complete.  So, using Organizer I did a "drag and drop" of my image collection's root file from the C: location to the external drive which happened to be the J: drive.  Organizer appeared to be running properly so I left it to continue overnight.  The next morning I discovered that only about 2/3 of the files had been moved.  There was a very cryptic message that said the opertion could not be completed because of "possibly unsupported files types, files with read only attributes.." etc.  I did not write down the actual message and it did not tell me where in the transfer the failure occurred.  After doing some detective work I discovered that many folders and files had been copied to the J: drive that were not appearing in the Organizer catalog and consequently were not being displayed.  Some folders had only a portion of their files copied.  Fortunately, the files were still visible and cataloged on the C: drive.  I did look at my files on the C: drive and there were some that for what ever reason had read only attributes.
 
The selected file, files, or folders should be copied to the specified destination.  At that point they should be added to the catalog, then the files should be deleted from their original location and the catalog updated accordingly.  If an original file is read only then it can't be deleted but the attempt to delete it should be reported as an inability to delete with no consequences imposed on the files that have been placed in their new location.  The "problem" should not be promoted to the status of a serious or fatal error that causes only partial completion of the overall operation.