Did a minimal install of RHEL3 i386 AS. Then used up2date to fetch redhat-config-xfree86 Then tried to use redhat-config-xfree86 Tool traced back, I don't have the screenshot ready, but os.execve was failing. I believe the tool was trying to launch the server, but there was no server rpm. Shouldn't redhat-config-xfree86 require XFree86 (packaging wise)?
This is fixed in system-config-display-1.0.4-1 in Rawhide. I added a Requires for XFree86.