Under WinXP, I got error "Couldn't open socket for incoming connections (socket returned error 10047)".
Can you confirm whether IPv6 is enabled or not?
I am away from that particular computer right now (and will be for next week, too). But IPv6 was definitely not used, not sure, if there is some IPv6 layer installed (probably not).
BTW, that PC has 2 ethernet NICs (plus some virtual connections like those from VMWare or OpenVPN). Hope this helps.
The standard 0.6.2 does work fine, connects without problems.