Just to chip in here - did you already follow the instructions Sila indicates above, and what's happening is that it's just not importing?
One thing to try is exporting a blank file from FrontlineSMS before you've done anything, and ensuring that your file follows exactly the same format and column headings.
Give it a go again, and if the problem persists, can you immediately send us your logs and let us know here when you've done so?
Further help and instructions can be found by following the link to our help files at the top right of the screen.
I hope this is helpful but do shout if you need more.
Thanks Laura, I'll do the 'blank import' and get back. thanks once again