Boot error messages

[Neben Kabon]

When I boot my G3 with YDL (also with a Knoppix PPC CD) I 
get some strange messages similar to that below:

hde: cdrom_decode_status: status=0x51 {DriveReady 
SearchComplete Error}

The (hex?) number is not always 0x51.  Can someone in 
general what these message are referring to?

My hard drive is not factory original, but I have been 
using it for several years without problems.

It will continue to boot O.K. with YDL.