Nobel,
We tried as your recommendation which was removing SCSI_PPA in our config. But we still have the similiar problem which has the similiar message, not the same exaclty.
James Bottomley pointed out that the imm driver is also broken on parisc. Can you try a standard config on your machine, such as the b180 config?
The problem is that many of these drivers are written with x86 hardware in mind and do not work correctly on other architectures.
You can try copying arch/parisc/configs/b180_defconfig to your .config and start from there, or download a prebuilt kernel from http://cvs.parisc-linux.org/download/linux-2.6/
Let us know how that goes. randolph