it looks like the routine utilized ObjectDBX to open the files and make the updates, which is very quick and effective, but with that and actually opening the drawing to modify you have to make sure no one else is in the file. I'm not positive that is your issue, but something to verify. Before you run this routine, make sure you don't have one of the drawing files open and make sure that no one else does either. I am not sure if it would be sensitive to others even accessing via a preview or thumbnail look as well. One way to test this is to make a copy of all the files to a new location that only you have access to and then run the routine. If it runs fine then you have found the issue, if not then work on to the next thought process.
Also something to note. updating hundreds or even thousands of drawings in batch processing modes is awesome. We can fix errors quickly and efficiently, but we can also SCREW UP hundreds or thousands of drawings just as fast. So always, ALWAYS make a copy before you process an update.
Good luck
