Seemingly, the filesystem is the responsible of the kernel load failure. A number of binaries in /bin, /sbin, /usr/bin and /usr/sbin have currently a size of 0. I suppose that this same reason is...
yesterday I was able to get a bash on the serial console (ie. the OS completed its boot and I started a session as OS user) with the same cable. So I don't think my problem is related to the cable......
I cannot apply the solution you proposed. This is a rented machine, the rental service didn't give us neither the OS CDs, nor a NIM server address... :(