PCI Parity and System Error on startup

I am running a Dimension XPS_R:

I just added a Belkin network card and USB 2 card. When the system starts it displays the following errors AFTER the POST one beep and before the OS loads (whether XP from hard drive or a boot disk makes no difference):

PCI Parity Error on Bus/Device/Function 0068h

PCI Parity Error on Bus/Device/Function 0070h

PCI Parity Error on Bus/Device/Function 0071h

PCI Parity Error on Bus/Device/Function 0072h

PCI System Error on Bus/Device/Function 0080h

PCI Parity Error on Bus/Device/Function 0080h

Specs from top of forum:

Dimension XPS_R:
Chipset: Intel 440BX AGPset.
Has 3 memory sockets.
Each socket has a maximum capacity of 128MB.
Minimum system RAM is 64 MB.
Maximum system RAM is 384 MB.
Uses SDRAM PC100Mhz.
Uses ECC or NON-ECC memory.

The Parity makes me think memory but why would it also say PCI and the memory has not changed and has been just fine?

Any suggestions of how to fix this?

The computer still boots just fine after displaying these errors and everything seems to work ok.

Thanks.