It's possible that this is due to Protected Mode in Reader X -- to check you can temporarily turn off Protected Mode in Reader under Edit > Preferences > General category and uncheck "Enable Protected Mode at startup".
Sadly, I have never had luck with the OLE Embedded Object that you put into Office application documents (Word, Excel, PowerPoint). The OLE objects embedded get corrupted and cannot be extracted. While it's true that there are two other instances where you could get this error:
1) The OLE server application (Acrobat or Reader in this case) is not properly registered with the system
2) Possibly Protected Mode/Protected View in Acrobat is blocking the execution of the OLE Server Application
I wouldn't bet on it.
In the future you may want to use a PDF Portfolio where you can attach both Office and PDF files within the Portfolio envelope.