I tried adding this to a simple page with your code and it worked here http://www.thosedigitalthoughts.com/test-2.html
When I use my version and swap out the form ID's it doesnt work however http://www.thosedigitalthoughts.com/test.html
Is there something I am missing from within Marketo. I get an error in console that says "Subscriber '280-LNO-408' is not valid"
(Assume you meant to respond to me, not Marcie.)
You aren't using the right pod ID for your instance. Look in a form embed code on your instance and you'll see where you're hosted.
You can see the error in your browser's F12 Console. Always look there first: