J Query Question - but could be CSS and its IE 7

Question

Ok so I know this is not Adobe specific but in my experience there are lots and lots of clever people about on this forum so I am hoping someone can help me out.
Basically I have built a photo gallery using JQuery (which is outside of my comfort zone - so have basically just robbed something from the net - legally I might add lol).
In IE 7 the last image in the thumbnail strip is wrapping itself around to the bottom of the strip and looks out of sequence.
Anyway here is the code.
                                    The White Lion at Alvanley - Village Pub & Dining                                
HOME
HISTORY
FOOD & DRINK
GARDEN
EVENTS
GALLERY
COAL BUSINESS
LOCATION
                                                                                            White Lion, Manley Road, Alvanley, Cheshire WA6 9DD
Tel: [phone]                        Sign up for our Newsletter                                                                                                                 
and for extra goodies here is the CSS
.ad-gallery {   width: 850px; } .ad-gallery, .ad-gallery * {   margin: 0;   padding: 0; }   .ad-gallery .ad-image-wrapper {     width: 100%;     height: 400px;     margin-bottom: 10px;     position: relative;     overflow: hidden;   }     .ad-gallery .ad-image-wrapper .ad-loader {       position: absolute;       z-index: 10;       top: 48%;       left: 48%;       border: 1px solid #CCC;     }     .ad-gallery .ad-image-wrapper .ad-next {       position: absolute;       right: 0;       top: 0;       width: 25%;       height: 100%;       cursor: pointer;       display: block;       z-index: 100;     }     .ad-gallery .ad-image-wrapper .ad-prev {       position: absolute;       left: 0;       top: 0;       width: 25%;       height: 100%;       cursor: pointer;       display: block;       z-index: 100;     }     .ad-gallery .ad-image-wrapper .ad-prev, .ad-gallery .ad-image-wrapper .ad-next {       /* Or else IE will hide it */       background: url(non-existing.jpg)\9     }       .ad-gallery .ad-image-wrapper .ad-prev .ad-prev-image, .ad-gallery .ad-image-wrapper .ad-next .ad-next-image {         background: url(ad_prev.png);         width: 30px;         height: 30px;         display: none;         position: absolute;         top: 47%;         left: 0;         z-index: 101;       }       .ad-gallery .ad-image-wrapper .ad-next .ad-next-image {         background: url(ad_next.png);         width: 30px;         height: 30px;         right: 0;         left: auto;       }     .ad-gallery .ad-image-wrapper .ad-image {       position: absolute;       overflow: hidden;       top: 0;       left: 0;       z-index: 9;     }       .ad-gallery .ad-image-wrapper .ad-image a img {         border: 0;       }       .ad-gallery .ad-image-wrapper .ad-image .ad-image-description {         position: absolute;         bottom: 0px;         left: 0px;         padding: 7px;         text-align: left;         width: 100%;         z-index: 2;         background: url(opa75.png);         color: #000;       }       * html .ad-gallery .ad-image-wrapper .ad-image .ad-image-description {         background: none;         filter:progid:DXImageTransform.Microsoft.AlphaImageLoader (enabled=true, sizingMethod=scale, src='opa75.png');       }         .ad-gallery .ad-image-wrapper .ad-image .ad-image-description .ad-description-title {           display: block;         }   .ad-gallery .ad-controls {     height: 20px;   }     .ad-gallery .ad-info {       float: left;     }     .ad-gallery .ad-slideshow-controls {       float: right;     }       .ad-gallery .ad-slideshow-controls .ad-slideshow-start, .ad-gallery .ad-slideshow-controls .ad-slideshow-stop {         padding-left: 5px;         cursor: pointer;       }       .ad-gallery .ad-slideshow-controls .ad-slideshow-countdown {         padding-left: 5px;         font-size: 0.9em;       }     .ad-gallery .ad-slideshow-running .ad-slideshow-start {       cursor: default;       font-style: italic;     }   .ad-gallery .ad-nav {     width: 100%;     position: relative;   }     .ad-gallery .ad-forward, .ad-gallery .ad-back {       position: absolute;       top: 0;       height: 100%;       z-index: 10;     }     /* IE 6 doesn't like height: 100% */     * html .ad-gallery .ad-forward, .ad-gallery .ad-back {       height: 100px;     }     .ad-gallery .ad-back {       cursor: pointer;       left: -20px;       width: 13px;       display: block;       background: url(ad_scroll_back.png) 0px 22px no-repeat;     }     .ad-gallery .ad-forward {       cursor: pointer;       display: block;       right: -20px;       width: 13px;       background: url(ad_scroll_forward.png) 0px 22px no-repeat;     }     .ad-gallery .ad-nav .ad-thumbs {       overflow: hidden;       width: 100%;     }       .ad-gallery .ad-thumbs .ad-thumb-list {         float: left;         width: 9000px;         list-style: none;       }         .ad-gallery .ad-thumbs li {           float: left;           padding-right: 5px;         }           .ad-gallery .ad-thumbs li a {             display: block;           }             .ad-gallery .ad-thumbs li a img {      display: block;             }             .ad-gallery .ad-thumbs li a.ad-active img {               border: 3px solid #a7907f;;             } /* Can't do display none, since Opera won't load the images then */ .ad-preloads {   position: absolute;   left: -9000px;   top: -9000px; }
However after a bit of validation action on the CSS it appears there are a couple of errors although not sure if this is what is effecting the page.
Any thoughts.
G

Answer 1

Persist.
I don't regret one bit taking the time to learn jQuery. Also, I generally find that errors I get with jQuery are usually just errors in the way browsers execute CSS or Javascript (mostly IE6 & 7!). jQuery is a brilliantly written resource.
I got an error the other day when I had blocks that appeared on click, but identified them with ids ( $("#someidhere").click() ). On older versions of internet explorer, it refuses to handle more than one element with an ID, so it would only let me show/hide one of my blocks. Don't be fooled though, that's a javascript error rather than a jQuery error (although it is seriouly bad practice to have more than one element with the same ID!).