I have made tests on a Italian windows 98 SE so it should apply also to other locales,
most of problems seams to be related to dns resolution.
I've made tests with and w/o dhcp and I got no problems, so your problems can be related to a non updated windows
or something that I cannot reproduce.
If you have usefull info about this and want to help post logs (like cannot resolv etc) I can provide test programs
to try to find the source of the problem.

As reference I'm providing versions of all involved dll:
ws2_32.dll - 4.10.2222
ws2help.dll - 4.10.1998
iphlpapi.dll - 5.00.1717.2
ipcfgdll.dll - 5.00.1717.2

since all of these dll are english even on Italian win98se I think locale is not involved here