Keynote File Error

On reloading keynote file I get the error message:  Duplicate key value '', text: ''

This forum discussion helped solve this, see the very last comment.
I had a blank line with a Tab in it. Deleted the tab, resaved, reloaded and the error was gone.

I have no issues with keeping blank lines in the keynote file as one of the comments states.

http://forums.augi.com/showthread.php?145647-Keynote-File-Error-Duplicate-Key-Value