New Post: Import Products from External CSV source?

I've tried importing by following the instructions offer under documentation. but ran into error:

System.ArgumentNullException: Key cannot be null. Parameter name: key at System.Collections.Hashtable.ContainsKey(Object key) at NEvoWeb.Modules.NB_Store.ImportCSV.getCSVcategoryXref(String[] strCSVlines, String CatMapping, Int32 intPRefCol, String FieldDelimeter, String FieldQualifier, String FieldEscapedQualifier) at NEvoWeb.Modules.NB_Store.ImportCSV.buildCSVProductXML(PortalSettings PS, String[] CSVlines, String FieldDelimeter, String FieldQualifier, String FieldEscapedQualifier) at NEvoWeb.Modules.NB_Store.ImportCSV.ImportCSVProducts(PortalSettings PS, String ImportFile, Boolean UpdateExistingProductsFlg, Boolean CreateCategoriesFlg, String RowDelimeter, String FieldDelimeter, String FieldQualifier, String FieldEscapedQualifier)

Please help.

Thank you,

Andre