[netspy]

Now I have removed all unnecessary style declarations and reduced to this code:

.tTip {cursor: pointer; color: #666; font-weight: bold;}
.tip {color: #333;}	
/*-----------------------------------------------------------------------------------------------*/
/*                                         TOOLTIP STYLES                                        */
/*-----------------------------------------------------------------------------------------------*/

.tip {
	width: 212px;
	padding-top: 37px;
	overflow: hidden;
	display: none;
	position: absolute;
	z-index: 500;
	background: transparent url(images/tipTop.png) no-repeat top;}
	
.tipMid {background: transparent url(images/tipMid.png) repeat-y; padding: 0 25px 20px 25px;}
.tipBtm {background: transparent url(images/tipBtm.png) no-repeat bottom; height: 32px;}

Now it works.