I have the image pasting problem with the support forum posts too. However, there I experienced something quite strange. In my last post of this thread, I got, when pasting the second image (page does not exist message), the first error (upload), but it pasted the picture all the same. To me it seems related to the picture size too.
I was confused because your message did not appear in the thread. I assumed you had sent it only by e-mail. In any case, it seems to be an intermitend problem. I was able to paste an even bigger picture into the post, as you can see.
I experience problems with the support ticket page. First, a minor problem, it seems, that the size of images I can paste into a ticket from the clipboard is quite limited. An image of 1391 by 260 gives
Working around by cutting the picture smaller, results in
after having hit the submit button.
I shall contact you by this forum instead in the meantime.