jQuery UI: jquery-ui-1.7.2.custom.css, theme: Darkness original got error on Firefox 3.5.7

jQuery UI: jquery-ui-1.7.2.custom.css, theme: Darkness original got error on Firefox 3.5.7

Hi people,
 
I downloaded the JQuery UI 1.7.2 theme: Darkness original  and when using it on Firefox 3.5.7 I got the following error messages:

jquery-ui-1.7.2.custom.css:

 

Error in parsing value for 'filter'. Declaration dropped.

LINE 18:

.ui-helper-zfix { width: 100%; height: 100%; top: 0; left: 0; position: absolute; opacity: 0; filter:Alpha(Opacity=0); }

 

 

LINE 74:

Error in parsing value for 'filter'. Declaration dropped.

 

.ui-state-disabled, .ui-widget-content .ui-state-disabled { opacity: .35; filter:Alpha(Opacity=35); background-image: none; }

 

 

LINE 76:

Error in parsing value for 'filter'. Declaration dropped.

 

.ui-priority-secondary, .ui-widget-content .ui-priority-secondary { opacity: .7; filter:Alpha(Opacity=70); font-weight: normal; }

 

LINE 282:

Error in parsing value for 'filter'. Declaration dropped.

 

.ui-widget-overlay { background: #5c5c5c url(images/ui-bg_flat_50_5c5c5c_40x100.png) 50% 50% repeat-x; opacity: .80;filter:Alpha(Opacity=80); }

 

LINE 283:

Error in parsing value for 'filter'. Declaration dropped.

 

.ui-widget-shadow { margin: -7px 0 0 -7px; padding: 7px; background: #cccccc url(images/ui-bg_flat_30_cccccc_40x100.png) 50% 50% repeat-x; opacity: .60;filter:Alpha(Opacity=60); -moz-border-radius: 8px; -webkit-border-radius: 8px; }/* Resizable

----------------------------------*/

 

 

LINE 297:

Unknown property 'zoom'. Declaration dropped.

 

.ui-accordion .ui-accordion-header { cursor: pointer; position: relative; margin-top: 1px; zoom: 1; }

 

 

LINE 311:

Unknown property 'zoom'. Declaration dropped.

 

.ui-dialog .ui-dialog-content { border: 0; padding: .5em 1em; background: none; overflow: auto; zoom: 1; }

 

 

LINE 334:

Unknown property 'zoom'. Declaration dropped.

 

.ui-tabs { padding: .2em; zoom: 1; }

 

LINE 399:

Error in parsing value for 'filter'. Declaration dropped.

/* IE6 IFRAME FIX (taken from datepicker 1.5.3 */

.ui-datepicker-cover {

    display: none; /*sorry for IE5*/

    display/**/: block; /*sorry for IE5*/

    position: absolute; /*must have*/

    z-index: -1; /*must have*/

    filter: mask(); /*must have*/  <---------  LINE 399

    top: -4px; /*must have*/

    left: -4px; /*must have*/

    width: 200px; /*must have*/

    height: 200px; /*must have*/

}/* Progressbar