It is complaining that the Total doesn't match the sum of the items in the cart.
If you can view source before copy and pasting the error codes I can see better what is going on. Please post the same message as before, but view source on the page first so that I can see it with the spaces and tags that won't show when viewed through the browser.
Then attach a copy of the confirm.php page and I can figure out how to resolve it.