Excel import result says - tags not available for editing

[gcassar]

I have the batch plugin and am running an import from Excel.

What does it mean when some of the results say

"The tag _Exif_Photo_DateTimeOriginal, is not available for editing"  and also
"The tag _File_Main_FilePath, is not available for editing"   (and lists the filename of each)

I have restarted my PC and still get the same result.   
What is the possible cause ?

[Phil Harvey]

I was hoping someone else might respond to this.  I don't know where this message is coming from.  All I can say is that it isn't coming from exiftool.

- Phil