Netscape error

[Tomt]

Hi everyone, 

        I have installed netscape and when I go and try to run it (not as root) 
I
get this message

Xlib: connection to ":0.0" refused by server
Xlib: Invalid MIT-MAGIC-COOKIE-1 key
Error: Can't open display: :0.0

Any idea what this is and how to fix it

Thanks