ok, for the error, use the Windows Explorer and browse to the site root, then delete the _notes folder from the site.
the code that passes the amount to paypal is:
$WA_PP_ECO_Do_itemized[0][$nextIndex] = "Amount" . strval($cartIndex+1) . "";
$WA_PP_ECO_Do_itemized[1][$nextIndex] = "".$CHG_cart->DisplayInfo("Price") ."";
add number format to that:
$WA_PP_ECO_Do_itemized[0][$nextIndex] = "Amount" . strval($cartIndex+1) . "";
$WA_PP_ECO_Do_itemized[1][$nextIndex] = "".number_format($CHG_cart->DisplayInfo("Price"), 2) ."";