Netserver LC3 System/Parity Errors with new cards

[Dizzy R. Kodeberi]

Hello,
I have an HP Netserver LC3 with 3 9gb drives in the scsi array and dual 500mhz katmai processors. I have been recently trying to set it up for video capture so I bought a Sound Card, Graphics Card, Video Capture Card, and also an IDE card to add extra IDE hard drives. My server has 6 PCI slots and 1 ISA slot in it but looking at the configuration it looks like some slots share IRQ's. I don't know why there would be 6 slots if only 3 are usable. I can plug in 3 cards at a time before I get parity errors but no more than that. Is there any solution? I've updated the BIOS as well because I thought that could be causing errors.
Thanks,
Dizzy