Here's a weird one. Today I think I identified the cause (or a cause, at least) for the Internal Server Error message we sometimes receive when posting or modifying posts. For some reason, this seems to happen when a post includes two or more consecutive dashes ("-"). I can't explain it!
Sometimes I include a series of dashes to divide a post up. After much trial and error I worked out that removing the dashes stops the error occurring.
So, if you get that error message, check your post for consecutive dashes and try again.