Error code 12 is generally the result of a resource conflict of type IRQ, DMA, Memory, or I/O.
You may run into this issue if another piece of HW on the same PC uses the same Interrupt that our RP Infinity ports use.
In most MP systems ACPI / APIC is in charge of configuration and Interrupt management. Proper use of these Advanced technologies requires that the BIOS, Operating System, and all pieces of the HW that use any of these resource types know how to behave. For instance if your BIOS is setup for ACPI and your OS is a non-ACPI installation, they will have a hard time dealing with each other. One other issue that needs to be investigated is the possibility of some other piece of HW triggering the Resource Conflict scenario. It is known that there are some HW that use resources such as Interrupts but never report them to the system. This type of behavior can also confuse the system and possibly create a resource conflict issue.
Please ask the customer to go to the BIOS and see if changing the current status of ACPI / APIC will make a difference. I'm afraid in most cases switching to a different ACPI configuration requires an OS reinstall as well. this is due to the fact that both sides, BIOS and OS, should be using the same ACPI configuration to properly communicate.