Well, once you've triple verified that you have the correct jumper settings for the card...
Remove it from the system and closely inspect the CPU connector, both on your A4000 and on the Cyberstorm. That is not a very well designed connector, and it's easily contaminated by dirt, as well as very fragile. I know it's boring as heck, but inspect each individual pin... I had a bent pin on my CyberStorm Mk2.
On a quick glance it looked fine, but I noticed it after close examination after the system wouldn't boot. I think I actually shimmed that pin on the connector slightly with a little extra copper trace to make the connection more stable. It's been a lot of years now, though. I forget exactly how I did it. I just remember not to remove the CS unless I have a darn good reason to. ;-)
