Categories

We recently started populating our product database but we seem to be having problems matching the categories in the import file to the categories that are already in the database.  For instance, we have the parent category on the database as accessories and the sub-cateogory is candles.  When we do the import, we have candles under the category name and we leave the  parent category blank.  When we import the category, PC will automatically create a new category call candles but put it under the root directory.  According to the manual, I don't have to have the parent categoy in the CSV import file unless there are more than 1 category with the identical name.  Can anyone help me troubleshoot this?  I'm using version 4.