Description of problem:
As talked per e-mail with you, I'm tracking down "my issue" and the 
corresponding patch in this bug report here, that the information 
isn't lost.

mkinitrd 3.5.24 always creates and tries to use /sys - even at 
kernel 2.4 and causes harmless but unnecessary error messages at 
booting time, so I worked out a patch that fixes the issue for me.

Version-Release number of selected component (if applicable):
mkinitrd-3.5.24-1

How reproducible:
Everytime, see below.

Steps to Reproduce:
1. Install mkinitrd 3.5.24 at FC1 or RHEL3
2. Install a new 2.4 kernel or recreate the mkinitrd
3. Reboot the machine and have a look to the booting messages
  
Actual results:
Patch is attached.

Expected results:
Fix at some time like I did it or better ;-)

Additional info:
This patch seems to be only for belong for the older (even aliving) 
3.5.x line.