tecra 9100 and qnx4.25

i bought a new toshiba tecra 9100 with a p4 cpu and am having hard time
getting qnx425 installed on it. it wont even boot from a 425 boot floppy.
the installation cd boots and seems to install qnx425 normally, but when i
try to boot off the hard drive, it locks up at “press esc for alternate os
…”. i was able to install and run qnx6 without any trouble (i need 425).
i was even able to boot from the qnx4 demo floppy. i have a teca 8000 which
runs 425, which i used to verify the bios settings.

any help or advise would be appreciated. thanks, shontay.