I don't use Word 2007 as I am still stuck on Word 2002 (XP), but I understand from the Microsoft link below that Normal.dotm is the equivalent of Word 2002's Normal.dot.
http://office.microsoft.com/en-us/word/HA100307561033.aspx
In your post you say you are working in "My Documents", so I assume you are opening files from there, and not from within Word. Things I would try;
1] Open Word, navigate to your file from within Word and open. Save the document immediately, then use Word's Close program option to close Word down instead of the "X" top right. Do you still get the same message?
2] If so, then I would delete Normal.dotm and let Word re-create it when you next open Word 2007. This will lose all formatting changes you have made up to this point. If you don't want to lose those changes, instead of deleting Normal.dotm, rename it to Normal.old, or anything similar. You can always name it back later if you wish. Then
3] Open the document, and close it and Word down again. Any error messages, or has that cleared it?
Mark
I was wondering if someone might be able to give me some direction.
I have an HP computer running Windows XP and Office Home and Student 2007. When I am working in my documents and go to close a document, below is the error message I SOMETIMES get:
"This file is in use by another application or user C:\...\Templates\Normal.dotm"
Then I cannot remember what it says...I just get out of that. I am still trying to duplicate this to see when it happens and exactly what the question and my answer has been. After I get out of that error message, I get this message:
"Changes have been made that affect the global template, Normal.dotm. Do you want to save those changes?"
I click on no. It goes to a blank Word screen and then I can X out of it.
Now SOMETIMES I get this error message when trying to exit a Word document:
"Normal.dotm was being edited by another Word session. If you save this document with original name, you will overwrite any changes made in the other session. Do you want to save the document using original name anyway?"
Then again I get out of it somehow and the next comes up:
"Changes have been made that affect the global template, Normal.dotm. Do you want to save?"
I answer no as above and then I get the same blank Word screen and X out of it.
When I go back into Word any changes I have made in AutoCorrect are saved there so it must be saving the normal.dotm file I assume. This happens whether or not I have made a change in AutoCorrect.
Any ideas? Thanks in advance.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic