First, I have Admin privileges. I have created a project. That project is linked to several screens, all of which contain the Summary field.
When I get to the Map Fields screen in the CSV Import Wizard, I map a CSV Field to the JIRA field, Summary, and enable the Map Field Value checkbox (actually, it doesn't matter if I enable or not).
The Next button is grayed out and I can't proceed to the next screen.
On the File Import screen, I get this warning when I choose the file: "The CSV file you uploaded contains non-ASCII characters. Make sure to set the right encoding." Encoding is set to UTF-8. Might that be a factor?