Blank post.php when publishing/editing (yeah another one)

Without making any changes to anything (other than publishing some new posts earlier) I suddenly got one of those blank post.php errors on one of my blogs today. When I publish a new post or edit an existing post I get redirected to a blank and completely empty post.php. The publish or edit takes place, I just don’t get redirected like I should be.

I’ve read everything I could find about errors like these, looked for hijack plugins (in the wb-options table), bad ping sites, broken plugins, server memory…nothing seems to apply. I’m open to any other tips to what can cause this weird and very annoying error.