I have no idea my friend. It makes sense what you are saying but every comment form "fits" to a specific item.. I'm waiting for William's solution..

I don`t know if you have unload the jquery in the k2 control pad. Because there is more than one jquery in my website,so I unload the k2 jquery ,and then ,the problem appear. Now I load the k2 jquery again , then everythine is ok. You have a try. I hope that you can solve the problem.