The incorrect Zero Rated Tax code is set in the tool, this will cause the invoices to error sync'd to Quickbooks.
Open the sync tool and select the entity. On the "Quickbooks" tab select "Edit" in the bottom left corner.
In the "Zero Rated Tax Code" field you have the incorrect value entered. Where you see the "." please delete it and add "none" if you're using US Quickbooks.
For other regions such as Canada for example: You can find the Zero Rated Tax Code by opening Quickbooks and going to the "Sales Tax" tab and "Manage Sales Tax".
Here you'll find the Code for Zero Rated Tax. By default it's set to "Z" but may have been changed.