Hi Raghavendra
Can u tell us on what EHP level ur in?? The above mentioned replies will serve u the best as this is the only solution we have left with. I suggest u to check ur MIME repository settings. Siddharth RajoraSagar GadreSamuli Kaski has already given the best answers. MALYADRI JWALA G clearly explained with screen shots.
Kindly come up with screen shot so that we can see the issue in detail.
Cheers 
Pradyp