I just tried this myself with a standard CSV with columns in the same order as the example in docs below, and the imported contacts were all listed with a big RED X under ACTIVE. The word "Active" appeared under the column heading "Current status" (AKA column #4), so why didn't I get a GREEN check box like I saw during the pre-import-preview?
UPDATED: Oops - looks like the documentation in 18.104.22.168 is out of date. Found that I need to write TRUE not "Active" now in the box. Found this on ning:
FYI - this was the documentation I was directed to from FLSMS:
from url: file:///C:/Program%20Files%20%28x86%29/kiwanja.net/FrontlineSMS_22.214.171.124/help/filemenu.htm