It does not appear that there is a way to import a .csv file successfully. Ive tried every approach mentioned without success. (Also to note: the "import CCR/CCD" button within the import/export section of the admin section, does not appear to work.)
If someone would attempt to import a .csv file and then post how you were successful, that would be wonderful! (on a stand alone computer, since I wouldnt want you to mess up your database!).
The patient encounters in the .csv format (even tried as .xml format) do not appear to import by any means which leads me to the conclusion that there is no reason to ever export all of your patient encounters as a .csv file from the import/export section of the admin screen.
If there is no way to successfully import the .csv file back into the system, AC users should stick to .enc files (encrypted backup files) exclusively. This will save a lot of headache and time if you want to restore files.