Copying from Notepadd

I am more an html dabbler than a programmer. I find it easier to start writing stuff in WP, then continue with longer/more complex posts and pages to continue work in Notepad++. But things suddenly go wrong for no apparent reason. For example:
http://podcast.roamer-educational-robot.com/other-projects/ all of a sudden his big white space appears between the text and comments. If I add more text now, it appears just below the comments.

I notice posts about white space Notepad and php, but I am not writing in php. Anyway, if anyone has any notion how to fix this, or am I wasting my time with Notepad?

[Moderator Note: Please ensure that you are embedding links correctly in your posts. Link corrected.]