Thanks for the reply. I verified the NIC used in the machine DELL T5500 and it seems that integrated Broadcom® 5754 Gigabit Ethernet controller is not listed in the compatibililty list. The last broadcom NIC mentioned is NetXtreme BCM5752M Gigabit Ethernet PCI Express. Do you see it as a possible issue. Also I looked at mentioned server list on the mentioned link but these links seems not be updated for new ESXi 4.1 version. Site mentions Dell Precision Workstation T7400 compatible with ESXi 4.0 & 3.5. The pc in question is new variant of same DELL series T5500.
If anybody has any other suggestion which I can try please let me know. I have been stuck on this issue for soo long now.
Thanks in advance!
The Issue is resolved post adding an Intel Based Express external NIC to teh DELL machine.