Once the (belated) list comes up, mapping typically goes routinely.
A (possibly) related issue is that, when mapping a problem share, sometimes I get a very long timeout until the error dialog box shows up.
Seems to be unrelated to firewall as I've got the I/P range for the workgroup set in the firewall cfg. I can ping all the machines no problem.
Using XP/Home, XPS 2.8Ghz, Cat5/802.11b/g connects. Problem same for wired/wireless.