Hi there,
Can you please try to recreate the preferences of Captovate 6.
Close the Captivate first
Then goto C:\Users\[current user]\AppData (hidden folder)\Local\Adobe\Captivate 6.0
Rename Captivate 6.0 to Captivate 6.0old and then launch Captivate.
Launch the captivate again.
Check whehter this helps.
Thanks.