Blank screen after submitting

Some people have reported similar problems, but got no answers. I hope I get some; Maybe this info will help:

When I submit a page in the admin interface I get a blank screen, though the change itself is saved.

The first time I had this problem is just after I submitted a change in a file I was trying to make using the built-in file editor. I was trying to comment some code in the “single page” file. I was trying to comment it using the HTML & PHP comment syntax: <!-- php -->.

Does that make any sense for someone?