Error in opening .docx file with MS Office 2012

I used MS Office 2012 and when trying to open a .docx file from My Documents folder, I received an error stating “There was a problem sending the command to the program”.

This error does not show until I opened my document files from within MS Word. By using MS Word 2010, all documents being checked are .docx file forms. After clicking OK button to close the error, MS Word is completely functional. What could be the cause of this error and how can I able to fix it?
Error:
There was a problem sending the command to the program
