When I installed the out-of-the-box kernel and installation configuration on my Pentium pc, it was not possible to write to /dev/lp0, or whatever should be mapped to the very standard pc parallel port... It turned out that kmod only loaded parport_probe, lp and parport. parport_probe was not able to find the pc parallel port. It turned out that putting "alias parport_probe parport_pc" in /etc/conf.modules solved the problem. parport_pc now successfully found the parallel port and it could be written to. I think that this is a big deficiency in the standard Redhat 6.1 kernel installation that should be fixed. I believe a significant number of the 6.1 users has a standard pc where the parallel port only can be detected by parport_pc. By comparison, the S.u.s.e 6.1 with kernel 2.2.5 correctly loaded parport_pc for successful parallel port detection.
I found that setting the following in conf.modules is better because it will also enable parport probing: alias parport_lowlevel parport_pc #host dependent option #options parport_pc io=0x378 irq=7
Fixed in latest beta of the installer.