Excel Sheet Criteria for Inteliwarp

Excel Sheet Criteria for Inteliwarp

  
What are the requirements on excel spreadsheet for Inteliwarp to work?  I am trying to import and excel spreadsheet and the Inteliwarp icon to perform this action doesn't work.
When dragging the excel file, only a forbidden sign appears when the spreadsheet is not in a compatible format, but if you use the option in the Import menu, Service Studio shows a detailed error message.

Take also a look at this two help topics:
http://www.outsystems.com/help/servicestudio/5.1/Using_Data/Creating_Entities_from_an_Excel_File.htm
http://www.outsystems.com/help/servicestudio/5.1/Designing_Actions/Import_from_MS-Excel_to_Record_List.htm

Best Regards,
Gustavo Guerra