Does Windows try to look for IPv6 AAAA records even when it does not have a routable IPv6 address?
Windows Vista and 7 will request AAAA lookups before A lookups if IPv6 is enabled (and the link local address isn't disabled). Windows by default will have a link local address and will therefor use IPv6 if available. Normally this isn't a problem as the AAAA lookup fails and it happily moves along to IPv4. Most applications however, will just skip straight to IPv4.