Help me Please connecting trough netbios

i have a problem - i have sever 2003 R2 standard Edition and computers
with xp home edition
i can connect to the server trough TS and can send ping to the server
from the xp computers
but when i tried to access the server trough netbios share (i mean \
\server\share) the server ask me for a username and password and when
i give him the username and password he give me a error
that go like that -
"\\server is not accessible. you might not have premission to use this
network resorure. contact the administartor of this server to find out
if you have access premissions.
logon failure: the user has not been granted the requested logon type
at this computer."
about the user that i tried to access with, is in the administartors
by the way - this network doesnt have a domain.
when i tried to access from the server to other computer its acees
fine and work fine.

please help me