I'm having the same issues... [see: http://forums.adobe.com/thread/871480]
Our course becomes stuck on a loading page if the user had previously failed the course, begun to re-take, and exited the course mid-way through their attempt. Bookmarking works fine if user hasn't failed the quiz yet.
If the user fails the quiz at the end they are shown the "re-take" button. If they "re-take" the quiz, but deiced to close the course at after a few slides, when they attempt to re-launch the course they will be taken to never-ending "loading" screen.
Some of the Adobe experts took my original course, and exported in Captivate 5.5, and this seems to fix the issue. Unfortunately this seems to be the ONLY way to fix the issue, but we are just glad this upgrade resolves the error, and that it's not something wrong with our LMS. We have about 15days left on our free 30day trial of version 5.5, then we plan to upgrade for $149. I suggest you do the same to see if that resolves your issues/errors. Good luck!
Can you share your project with us ? If yes then please upload the course to acrobat.com and share the download link.
Write to me at ashwin at adobe dot com
Ashwin Bharghav B
Adobe Captivate Team
hi Yamaha, did you ever fix issue? pls see my response above if that helps.
not sure known bug is fixed with 5.5 upgrade; other users have reported the bug in 5.5: http://forums.adobe.com/message/3235859#3235859