My RHEL WS4 system showed error in network cards, although network was working (internet, ping, telnet). When I rebooted, it went into kernel panic. How do I come out of it?

Good guess that you've got a failing board on your hands. Start removing NICs one by one. Reboot until you find the "odd man out," which will be the card that's in your hand.

Software goes apesh*t when hardware goes apesh*t. The reason why I'm saying that this is "undoubtedly a hardware problem" is that the system was working fine, and that it was beginning to report network-card errors, and the only thing that you did was reboot. Obviously the device-initialization code is encountering those same errors. (Did you happen to notice which card(s) it was complaining about? If not, use the process of elimination.)

After doing a lot of searching, I finally dared to crash the system and boot up again. This time it came up properly. I did not find any record of the error in any of the log files I checked (boot, dmesg, messages etc). The 2 NIC cards still show the error and still work. I am replacing the hardware soon, anyway, so it just has to stay up for a few mre weeks. Thanks for the input, though I saw it so late. o