running oracle enterprise linux
the Oracle installer keeps telling me that my DISPLAY variable isn't set. however echo display clearly prints ":0.0"
logged in as root I am able to run xclock to launch the app, but when I "su oracle" and then run xclock it refuses
[oracle@devsebl ~] xclock
Xlib: connection to ":0.0" refused by server
Xlib: No protocol specified
Error: Can't open display: :0.0
how can i give the oracle user permissions to use the display??