ACPI boot problem: Invalid block length...

[linuxguy]

My F9 kernels don't boot reliably. 

Linux kernels have thrown an "ACPI: Invalid PBLK length[0]" error on my
HP ZD7280 laptop for as long as I can remember.  

What changed with the F9 kernels is that the boot process will now hang
9 out of 10 times.    1 or 2 times out of 10 my laptop will boot.

What this means is that I must power up my laptop over and over to get
it to boot.

2.6.25-14 is more prone to boot.   1.6.15.3-18 can be very hard to get
to boot.  It seems to help if I boot -14 first and then boot 3-18.

How can I fix this ?

Thanks