If the cdrom is connected by a pcmcia card and DSL begins to boot from it but then fails... Try booting like this
boot: dsl ide2=0x180 nopcmcia
This works!
I have a Sony Viao Picturebook. Model is slightly different than original post: PCG-C1X
Same boot symptoms as original post and same fix.One month later. Ive got DSL installed debian style had to borrow another CDROM in the end. Thanks to Roberts for his efforts
original here.