Are you posting the .enlx version of your EndNote library to Sharepoint? Based on our tests, this should work just fine. Your research group colleagues will just need to re-save the file as an .enlx to check the library back in to Sharepoint.
If you are experiencing something different, please let me know and we will look into it.
It should be noted that it’s not recommended to use Sharepoint for active use of your EndNote library.
There are a few known issue with opening a library on a sharepoint.
Namely, it appears that libraries opened in a Sharepoint environment are easily corrupted.
Additionally, you may get a generic “EndNote Error” when attempting to open the library.
In this cases, it’s recommended that you make a local (either local drive, or local network) copy of the library, and use it, instead of the Sharepoint.
I believe that JasonR was referring to placing a library on a Sharepoint for the purpose of making it available to others for downloading to their system, and using.