I need to clarify a couple of things before I can move forward with this. Have you made any edits to the site or the checkout page with eCart? The reason I'm asking this is because I have PowerStore 2 setup and have no issues with the default code. If the code has not changed we can move on and look at another part of this.
Also, what is the result that you get if you use the direct pay checkout (enter cc into the checkout page and submit)? Do you get a successful transaction when using it this way? Please post back with these details and I will try to help you get this resolved as quickly as possible.