I will send both Captivate 6 & 7 files. We are not having trouble with Captivate 6, but only with 7. (Actually, we were kind of forced to upgrade to Captivate 7, since our team needed another copy of the software and Adobe only sells the latest version, which means we all needed to upgrade.)
We are working on Mac OS 10.7.5, and have the latest version of Flash (11.8.800.94). We have tested the files on both Firefox and Safari with the same results. Also, as I mentioned before, if we take a Captivate 6 file that has been working correctly, and then publish it with Captivate 7 there is a delay with that version, which did not exist in the Captivate 6 version.
It should be easy to replicate the issue, and I have included published files for comparison. When switching slides in the Cap6 version the answers are always obscured, but with the Cap7 version there is often a delay which clearly shows the students the answer for a moment.
Let me know if you have any other questions.