CSV Import fails in Mapping at Line 292

For three days running now, I have attempted to upload a CSV file to my site, and get nine (9) iterations of this error message each time:

[22-Mar-2016 11:07:40 America/Chicago] PHP Warning: Invalid argument supplied for foreach() in /home/indexvir/public_html/plugins/CsvImport/forms/Mapping.php on line 292

File has nine variables/columns, so I presume that the number of "invalid argument" errors is a result of that form.

I looked up all the posts that I could find here concerning CSV loading problems and sensed that this is a file-format issue often noted; so I tried to upload CSV files generated in both OpenOffice and LibreOffice, but got those error messages again (indeed, the LibreOffice variant locked up Windows Explorer on my Win 7 machine).

I am using the Reclaim Hosting service, with Omeka version 2.3.1, if that matters. I have also enabled all error logging services (both in host and Omeka) in order to try to track what is going on here.

That seems at first glance like it isn't the usual file-format issue. Not sure exactly what it might be, but more of the following info might help:

What browser are you using?
What version of CSV Import?
Since the error logging is on, there should be a long stack trace under each of those errors in the logs. Those might help, too.