First let me start by saying to you,
"Thank You Sir for re-editing this macro." 
I deleted all macros, only had one, and created your macro back into Word. At this point in time, still had some files in specified directory used for modifying of files.
Start Word, ran your macro, selected the Directory where the files were being stored that needed the macro to be ran on and, it failed, but on the following line:
Set oDoc = Documents.Open(strPath & strFilename)
So decided to shut down computer completely and start it back up again.
Started Word again, then your macro, again it failed on the same line as mentioned above.
Decided that maybe running macro on 20 files might be a bit much, so deleted that 15 files. Don't worry, these were only copies of the originals. Try it again, still failed.
Shut down Word and restarted it from the command line running the command:
winword.exe \m
This is to start Word without running any AutoExec macros, and guess what it failed again, same spot.
At this point in time, I was determined to find the cause on my own, if possible. So I started by replacing the files I had with other files that needed to be corrected.
Shut computer down and restarted. Started Word back up, ran your macro, selected the Directory where the files were being stored that needed the macro to be ran on and, IT WORKED!!!
Now why did it work this time? Went back to look at the files I had removed and the only difference in their file names was one had a number at the beginning of the it's file name. I wondered if this was the culprit?? But first, I wanted to keep running the now working macro for awhile. Ran about 300 files through, with sometimes having 80 files to be gone through, NO Issues.
So now is the time to that numbered file again. Placed it in the same directory along with the existing newly modified files. Ran the macro again, it failed. Now I was thinking why did it failed, so I renamed it without a number start off. Re-ran macro, IT WORKED.
Now tried another file that had a number at the start of it's file name and low and behold, it did not fail. It was the file itself, do not know what the issues were that kept the macro crashing, but I have attached for others to try as well. It does not have any viruses and etc. in it.
Thanks again sir for your hard work and time.
Bill