During text-mode install, you can use [Tab] to move between the fields and
buttons, and [Space] on a button is like clicking it.
On the dialog box titled "LILO Configuration" ("The boot manager RedHat
uses can boot other operating systems as well." where you choose
partitions that will appear in LILO) you can [Tab] to the buttons, but
[Space] will not select them. You have to use [Enter].
*** This bug has been marked as a duplicate of 11689 ***