No, it works without an internet connection. But you need to have a deck stored in your home directory before X-Terminal can load it up. Like Stefan says, you can download a pre-made deck at

http://ichi2.net/anki/wiki/ExtraDecks

just save one of the files, and ankimini will load it up in the browser offline. You may want to create your own decks in time.
You just need to register at http://ichi2.net/anki/
download the full-featured program which allows you to create your own cards then save them in your N810.

You can also do this online, without downloading the software.