Deepa,
There's really nothing I can recommend at this point to fix. I'd have to suggest submitting a bug-report to Facebook. You can do so at the link below:
developers.facebook.com/bugs
You'll want to submit it while logged into Facebook as the admin of your Application. Then, use the search box. Type "Like Button" and then click "Create New Bug Report". For Title, say something like "Like popup shows wrong information". Then in the description area, detail everything you've posted here.. your Open Graph tags are correct, the post in the user's wall appears correct. Everything seems right, but the URL is wrong *only* in the popup. Make sure you mention that is your old URL, but it's no longer used. Then, fill in the rest of the information as best as you can.
Hopefully, they'll have an answer for you, but I've exhausted all ideas and the issue is not being caused by JFBConnect in any way that I can tell.
Very sorry for all the trouble, and hopefully that will get you going soon.
Thanks,
Alex