Several possibilites to try:
1. Is Excel installed on your machine?
2. In Excel, Tools Options General and uncheck Ignore other apps.
3. In Windows Explorer, Tools Folder Options File Types. Scroll down the
list and ensure that .CSV and all .XL* files are set to open with Microsoft
Excel.
4. Right-click on the spreadsheet image in the doc. What do you see on the
context menu - Format Object or Format Picture? If the latter, then the
author in fact inserted only an image, and not an editable object. Perhaps
the other users who can edit have a different version of the doc.
Happy New Year!
--
Ted