We have all current firmwares on HP C7000 blade chassis using virtual connect. We removed a blade running vsphere 4 update 1 to add RAM. After replacing we get this "no compatible network adapter found" error early in the vsphere 4 classic boot process. It also has the same problem if attempting to do a clean install.
This blog post saved the day, after VMware and HP support could not! Another reason to spend plenty of time on blogs!
In short, you have to rerun the HP Firmware Update boot CD again after taking a blade out of the chassis and it fixes the network driver issue.
Per the blog this effects Xenserver 5.5 as well.