Trouble encountered in the new version of Microsoft Office 2007

I encountered an error while I was using the new version of Microsoft Office 2007, I installed this new version on my computer as a replacement from the old one I used; Microsoft Office 2003.
The error occurred when I was updating a schema.
Here is the picture:

Error:
Microsoft Office Word
One or more schemas you have selected cannot be used in this document. A
schema may not be available, may not be valid, or may require additional schemas in order to function correctly.
I don't understand this one, please help me guys.
