Currently it is not possible to import a folder containing several bitexts. I think that with the use of AlignRobot etc. it would be a great if a whole folder of bitexts could be imported.
Bitexts automatically created during the night, can be imported in the morning when the translators start there work.
Thanks Igor, I've added that to the wiki article.
If you choose a folder with bitexts files instead of one file, CafeTran will import all the files in the folder, just like regular TMX memories. See the menu Memory > Import > Import bitext memory...