ibook autosaved now won't open saying its the wrong format

Hello I have been working on my iBook for quite sometime. I would open up iBooks Author and work everytime.

It has been a while since I did any work on my book. This time when I opened Ibooks Author my ibook did not show up.

On searching all my files I find the book in iba format. But I am unable to open it. When I try I just get The document “2C1687D4-CE5C-463A-837A-E9781F21F7EF” could not be opened. The file isn’t in the correct format.

It seems like its in the cache, sessions folders. I do not know how to retrieve months of iBooks Author work

Thanks,

Dr. Gupta