Commented Unassigned: 0x800700C1 Error Message [8803]

The properties are shown at the bottom of the explorer page, but after I type a new value in a field, like Title, when I select save, I get an error message:
Error 0x800700C1: MyFileName is not a valid Win32 application.
I am running 64 bit Windows 7 and the file is a pdf.
Comments: ** Comment from web user: klembeck **

I don't see an attached image from you, but anyway there seem to be a few problems. I have been trying to figure out how to fix them but haven't had any luck so far. For example, I tried reinstalling the 64 bit redistributable, but msvcr100.dll still says x86 in Dependency Walker. When you said all modules in the second pane up should be x64, is that the pane you meant? I only see CPU in the pane where it has msvcr100.dll as x86.

I am attaching a screen shot of Dependency Walker.