Adding and deleting references in a Word file on two computers

I am using Endnote X1 on an iMac with operating system 10.6.3. I am having a problem with the cite while you write function. I have the identical program on my desktop computer and laptop. The article file on the laptop was at one time an exact copy of the desktop file, but over time the desktop file has been increased.

Over the weekend, I did some editing on the laptop and removed some references from a file. Today I took the file to work and attempted to add some new references to the Word 2008 file, but got an error message, " a COM exception has occurred" and below the exception statement was " command is not available". The command I was using was “insert selected citations”. I tried to reformat the bibliography, but got the same error messages. I created a new Word file with some of the text from the problematic file and was able to insert references into the Word file without problem.

It looks like Endnote has a problem working on a Word file with two computers with main library files that are not exact duplicates of one another. I could be wrong, but seem to recall having edited a  Word file on both my desktop computer and laptop computer, but this time it won’t work.

Any help resolving this problem would be greatly appreciated.