Hi Trent,
your code is ok, but the Save button is disabled on the first tab, so the click is swallowed by the button. (clicking on disabled buttons does nothing by design.)
Fortunately there is a JavaScript method to enable the button (and a JavaScript method to do the save) so change
p_web.Script('$("button[name=''save_btn'']").click();')
to
p_web.ntForm(loc:formname,'enableSave')
p_web.ntForm(loc:formname,'clickSave')
Cheers
Bruce