Can you explain what do you mean by 'can't click Send'? Does button disappear or you click on it and nothing happens?
Provide more details and screenshots, please.

The button is visible but you can't seem to click on it or even highlight whilst placing the cursor over it.

As I can see from the screenshot, image wasn't attached properly. I cannot reproduce the issue neither on my local install nor on your website.

I have the same problem with attaching video but this not happen all the time.

Thank you for trying but from what I see you wrote a post first then added a new post without writing anything but just adding a picture this will not give the error, I can post pictures all day long with no error. You need to add writing AND photo/picture in the same post to reproduce the error.

I write my post then try to upload an attachment, same thing I have done for several years with Facebook and MySpace, except I am unable to post.

Can anyone provide me with exact steps to reproduce the issue? Everything works fine on my local install. That's weird.

Yes write a post and attach a picture to the same post then try click submit, as Hau Young stated in the earlier post this doesn't happen all the time but for me I just gave up trying to add my post because it continued to do the same thing :(

It's as if the photo/video is to big for the posting area and covers the button thus not being able to hit submit?

By the way that's a damn nice picture that you posted lol.

Slash is correct, I was able to post writing and a picture earlier yet I tried again later and I got the problem again. But as Slash said if you hit the little cross it usually fixes the issue. I also tried that but it didn't work for me?
Ok so it seems this only happens for Admins and not users of the site?