Just to let you know, I tried in another browser and it works fine. In Google Chrome, all options are displayed, but not in Firefox.
I am having this same problem. The import option is not displaying on the admin screen. I have looked at the screen options and “Data Import From Pre-v3.4” is checked. Even though everything is checked, only “Group Management” and “Set of Fields” are showing up. Is there another way to import your data?