Same problem.
I just did a fresh install (in a separate directory and Sql server), and installed the demo product set.
I tried to purchase a $5 gift certificate - a virtual product.
Ran into the same problems as before. Had to follow the first instructions (add the '(int)' in front of the format id values), and then witnessed this same error:
Code:
1366 Incorrect decimal value: 'f' for column 'value' at row 1
in:
[INSERT INTO zenorig_orders_total (orders_id, title, text, value, class, sort_order) VALUES ('2', 'Free Shipping:', '$0.00', 'f', 'ot_shipping', '200')]