Kernel 2.6 hangs in Knoppix 3.7 on Toshiba Tecra 9000

knoppix26 boot option hangs at the start, immediately after two lines of progress dots followed by clearing the screen, at the point that the penguin graphic should appear.

OK, I know I can still use the standard 2.4 kernel, which works perfectly, but presumably that will be removed from the standard Knoppix build at some time soon.

This is probably a kernel problem, because Mandrake 10.1 install CD (kernel 2.6.8 ) behaves exactly the same.

Kernel 2.6.3 (Mandrake 10.0) works perfectly on this PC with boot options:
acpi=ht pci=usepirqmask vga=792

LATER - it is not hung, just sleeping! After about 70 seconds inactivity normal booting resumes. (Mandrake 10.1 install CD does the same.)