You will get the same result when using the default phplist generated subscribe page: http://www.michiganjapan.com/wordpress/ ... cribe&id=1
Apparently the blank page issue is not your custom form, but something else. Did you activate the list (newsletter)? Try creating a new list and make sure you click on "save and activate"
I also noticed that your phplist generated subscribe form contains a custom attribute for the email field (i.e. attribute1). Phplist already has a field called "email". So remove/de-activate attribute1 from your subscribe page, both custom and phplist generated.
Continued in this thread: http://forums.phplist.com/viewtopic.php?t=9331