Firewall blocking file transfer

I have two office computers using ESS, one has Windows Vista, the other XP. They've both been fine, able to transfer files between each other perfectly ok, up until the end of last week when I updated both of them to 4.2.67.10, as they had been on 4.0.something.

Anyway, now the XP computer can see the Vista computer fine and share files with it, but the Vista one can't see the XP one, double clicking the shortcut on the desktop says it can't find the network location, or something along those lines. However, if I disable, then re-enable the ESS firewall, it can connect fine. Now, obviously this has to be a problem with the firewall setup somewhere, otherwise simply disabling and re-enabling it wouldn't cause these problems, but how do I stop this happening? Everything was working fine before the update, and I selected to carry the settings over, so nothing should have gone wrong like that. And having to disable and re-enable the firewall once a day is going to get fairly annoying

Its a wireless network, if that helps.

 

did you place your network in the trusted zone on both comps?