A demi newbie question.

I recieve an arror that the oracle installer cannot open "localhost:0.0" The first time I installed oracle 10g on Fedora (C1) it worked. the second time I decided to re-install the OS and and write a manual for installation of Oracle 10g on fedora. However the second time around, Doing the same procedure, when I ./runInstaller, I get an error that the xhost cannot open at localhost:0.0! Any Suggestions?