Magento – Magento 1.9.3.0 file was not uploaded error

So....I have to assume it was some permissions issue, but I had already put everything to 777.

Anyway...I changed my php.ini to point to a directory inside my websites home directory var/tmp in my case and now it works fine.

Jim

The message is intended to mean that the filename of the file you are importing doesn't have a file extension. That is to say the file you are selecting to import is called something like customers rather than customers.csv. It attempts to validate the file extension as this determines what type of adapter to load (csv, xml, etc.).