Hi,
Im using version 1.39h and i have the Stock By Attributes mod installed (i believe this could be the only one affecting this).
When a customers adds a higher quantity of an item than i have available its meant to display *** next to the item, but it doesn't. It displays the "Products marked with *** are out of stock or there are not enough in stock to fill your order.
Please change the quantity of products marked with (***). Thank you" warning, but if you have multiple items in your cart you have to find out what is out of stock yourself. Also it doesn't display how many of each item i do have in stock.

I have "Show available stock level in cart when less than order" set to true.

I hope i've explained this properly, but feel free to take a look yourself. The site is www.purpleandblackalternative.co.uk/store

thanks,
Alex