Reproduced here:
http://stirus-11828-6082.show.tikiwiki.org/tiki-sheets.php
u: admin
p: 12345
I tried the following:
1-created a spreadsheet with two columns; row one had headings, row two data
2-exported the spreadsheet in CSV format, UTF-8 character set
3-renamed the export file
4-edit the exported file with UltraEdit; changed one field; saved with UTF-8
5-created an empty spreadsheet
6-ran import CSV with UTF-8
7-no data imported, and the sheet just says "Array".