Shirley,
The process of data import was described here: viewtopic.php?f=21&t=815
I don't know what do you import and where. Can you describe step by step what are you doing?
What data do you import?
What do you use to import data?
Paste some sample here as text or attach a file containing some data that you are trying to import.
You should be able to attach a file with almost any extension.