Thanks Aakash J and zXI_Gamer for your valuable inputs.
zXI_Gamer :- I have gone through all the links which you gave , but i couldn't find the solution. I am facing this problem on ESX 4.1 U3 (On the second link which you have mentioned, it says it is fixed in ESXi 5.0), so thought of raising this question. FYI, there is no CPU reservation at all.
Aakash J :- if you want any specific entry from "esxcfg-info" output i can post it, but i shall not be able to post all the information of esxcfg-info output, since it is againt the policies of my firm.
Output of "vmware -v" :-
VMware ESX 4.1.0 build-800380.