yast2 problem in stock 7.2 Pro ?

Thought I'd try yast2 on my testbox for 7.2 : root@papa:/home/deem > yast2 Xlib: connection to ":0.0" refused by server Xlib: Invalid MIT-MAGIC-COOKIE-1 key y2controlcenter: cannot connect to X server :0.0 What's this problem ? /Dee