Images not uploading to posts

I am having a problem with the new version of the media manager in WP 3.5. When I try uploading images from the media manager I get an “error uploading – try again later” message. Moreover, I cannot seem to be able to access any of the images I previously uploaded.

Curiously enough I have no problem uploading pics to the gallery or accessing the pics from the gallery. Additionally, the pics show up in the gallery even if when trying to load them in the post I got the error message.

Also, I tried retrieving the image for the post using the url of the pic provided in the gallery, but that also did not work. In that case a link with the title of the pic shows up but no picture…

What can I do??