XML Import fails with obscure error descriptor

Hello

I'm trying to import task details into an existing project in Clarizen and all I get is an error.

To Import the task details I have saved my project as both CSV and XML then I do the following:

a) Open my project in Clarizen
b) Scroll down to 'Wok Plan'
c) Click 'Utilities'
d) Click 'Import'
e) Select the CSV file
f) Click: Open

I immediately receive the error:
No data was found. To import data, please ensure that the relevant Work Item headers begin in the first column of the Excel.

Any assistance is appreciated.