quantity drop down have problem

i want quantity step as drop down box



in stock : 9999

quantity step : 1

list quantity step : 10

and success , i have quantity box with drop down list from 1 - 10



but i have problem.



when add to chart



i have 2 notice







The quantity of the product Organic Arborio Rice in your cart has been changed to allowable.



The product(s) have been added to the cart



, no product add to cart. please help us to fix it.



cs cart version : 2.0.6