Hi,
If you want to upload a CSV file, the best is to put it in a zip file. The "CSV" extension is not allow in Kunena uploads.
It is strange that you can upload via the text field and not via the upload. It uses the exact same code, just that the upload read a file uploaded and text field read a text submitted.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.