Fatal Error when Opening a Captivate File

Hi

I am trying to open some older Captivate files on a mac (MacBook Pro Retina, Mid-2012 running OS X 10.9.5).

I have tried opening with Captivate 5.5 (I do know they are not older than 5.5 files but believe they may be 4.x) as well as Captivate 7 and 8.

I have cleared the cache and manually removed the backup files from Documents --> My Adobe Captivate Projects.  I even tried to download and run the dcache.zip (air application) but nothing seems to work.  I have 6 legacy projects ranging from 8.9 MB to 12 MB that I really need to recover for a client.

Any help would be appreciated. Apologies in advance if there is already a solution in the forums but I could not find a suitable solution that worked.

thanks in advance.

-greg