The table may not be supported for table data checkpoint, however, depending upon the properties, methods, etc. available on the table to TestComplete, you can write your own script code to validate the table data if you need to. This is what we used to do back before there was ever anything called "checkpoints" in TestComplete. :)
If you can post screenshots of the object properties and methods on the table you wish to work with, we might be able to give some pointers on what to try.