The comments plugin requires an application id error

On your site, you're using jReviews and JFBConnect. Normally, this is fine, but you have a different application ID configured for both. This is definitely a problem as it will confuse Facebook in more areas than just the comments. Please try to use only one Application ID, or disable jReviews Facebook functionality to remedy the problem.

You don't need to get rid of the jReviews functionality, just update the application ID in jReviews to be the same as what you're using in JFBConnect (or vice versa). If you get that done, and still have the same problem, let us know and we'll try to help you further.

Iveth,
I just looked, and am seeing the error in IE. Can you please try disabling the following extensions, temporarily, to see if it fixes the issue? It will help us narrow down the problem:
1) jReviews - This is including it's own Facebook functionality, which may be conflicting
2) The Social bookmark extension that's adding the Tweet and Like links at the top. This extension is including the en_US version of the Facebook Javascript API which also may be conflicting.

Until we can narrow down the cause, I don't have any good answers. It definitely seems like a conflict somewhere, and that IE is just loading things in a different order than Firefox and Chrome, which is why you see the error there. If you disabling things, and it starts working, please let us know what extension(s) causes the conflict.

Thanks