You forgot to Capitalize 'Walter' ! You forgot to Capitalize 'Walter' ! Aaaaarrrggghhh......
OK, sorry, but every time I see this one, it makes me lol. The only possible way the Form.submit() method could be 'not support[ed]' is if you've over-written it. Like so:
<input type="submit"
name="submit" />
Form.submit now contains a reference - to a button. Not much point in calling
that. I have no idea how browser manufacturers let this one slip by, it's such an obvious pitfall. Join the club.
Submitting a form the usual way - submit button, image, hitting <enter> in a textfield, doesn't call Form.submit(), which (I assume) is just a JS wrapper. That's why they still, erm, function.
Just ignore all the other silly advice - except that 'Walter' business of course - and go back to what you had, with a new name. Walter.