ACPI-Problem ------ Howto acpi-off for the clients

Hello
I have a problem. I have eight old Siemens Pro C5 pcs as terminals.
The boot process under Edubuntu Breezy was fine (but slow)
Now I changed to a Edubuntu Dapper system, and there is a new unknown 
problem.
The first fault message is "ACPI unable to locate RSDP" and the result 
is at last the well-known bash-shell.

In the BIOS of the Siemens PC is only APM no ACPI function.
Is there a possibility to built in the parameter "acpi-off" for the 
kernel-boot-process for the clients?

Where in the boot process (script) have I to build it in?

Thanks
Reiner