4.6.4 is stricter when loading WSDL, which is affecting some users that have WSDLs that are not in UTF-8. If you want to use other encodings, you should add an XML declaration like this:
<?xml version="1.0" encoding="ISO-8859-1" ?>
This may be annoying to those affected, and I think we should show a friendly error message to the user (if error messages are ever friendly), but SoapUI is really helping you find a potentially serious problem with your WSDL. You shouldn't assume that every client has the same default encoding as you, and if the encoding is not specified, SOAP clients (actually, XML processors generally) are supposed to assume that the encoding is UTF-8.
Hope this helps!
/Manne, SoapUI developer
