I just installed the UserForms module (0.2.0). I tried adding a form, typed in the name and whatnot, and when I go to the forms tab and click the button to add any type of field and the page reloads to a completely blank page (URL at top is admin/EditForm). When I go back to the admin page, it never added the field. Not sure if I can provide any other info on this as it doesn't seem to produce an error..dev mode doesn't say anything, firebug doesn't say anything.. I'm at a complete loss here.
Strangely enough, just tried it again and this time when I clicked the add button, it still didn't add the field, but the page stayed there but all it did was flash a little "saving..." then "Saved" message at the bottom of the screen.