The system in question has a PS/2 keyboard and a serial mouse, and, using RH 6.1's graphical installer, the mouse does NOT work during the install process, making it rather difficult to use. Note that the mouse works fine once the installation is finished, as I am able to select the correct mouse type during the install, and the installed system thus gets set up correctly. I have to suspect that the installer is seeing the PS/2 interface and just assuming that a mouse is connected to it, without actually checking that such is the case.
This issue has been assigned to developer for further action.
*** Bug 5558 has been marked as a duplicate of this bug. ***
Issue is resolved in the latest beta installer.