We haven't had any other reports of this so far. Right after this happens, try pressing ctrl-shift-e. This will bring up the Internet Explorer window SuperManager is using the browse your Yahoo! Store. Tell me if it is showing an XML file or if you see an error message. If it is an error message this may tip you off as to what is happening.
If not, there could be an encoding or other error in the XML. When this is the case, it is usually caused by some anomolie in one particular order. In this case, you can try using "Actions", "Get Orders..." to get one or a few orders at a time until you reach the problematic order. Then you can export that order manually from your Yahoo! Store and send it to us so we can evaluate the problem.