XP SP2 and SMS 2003 console connection

I have two users running SP2 without the firewall running, and having run the dcom work around, and they still cannot connect to the SMS 2003 site through the MMC. one of the users just upgraded from 2000 where they had no problem connecting. i have recently re-installed the SMS administrator console on the box, but it did not help. does anyone have any ideas on how to get this thing up and running? thx,

bryan