Jquery slider Lightbox links not working in Chrome/FF but working in IE [closed]

Question

Alright this question is pretty complicated to explain, so please bear with me.

I'm using a jquery slider on my portfolio site to display my work. I've implemented a lightbox (I used this tutorial) because I'd like the user to be able to click on any image in the slider and then be presented with a lightbox gallery.

I've implemented the following code and it is working in IE, but it's not working in Chrome/FF. When you click on a portfolio project on my site you should be able to click on any of the images in the slider, however this functionality only works in IE.

<a href="<?php echo '' . $image_details[0]; ?>" rel="portfolio-gallery">
<img width="<?php echo $desired_width; ?>" height="<?php echo $desired_height; ?>" class="slider-img" src="<?php echo get_template_directory_uri() . '/timthumb.php?src=' . $image_details[0]; ?>&amp;h=<?php echo $desired_height; ?>&amp;w=<?php echo $desired_width; ?>&amp;q=90" alt="<?php the_title(); ?>" />
</a>                                                          
<?php } else { ?>                                                           
<a href="<?php echo '' . $image_details[0]; ?>" rel="portfolio-gallery">
<img width="<?php echo $image_full_width; ?>" height="<?php echo $image_full_height; ?>" class="slider-img" src="<?php echo $portfolio_img_url; ?>" alt="<?php the_title(); ?>" />
</a>

I've narrowed the cause down to the way that the browser is interpreting the initial portfolio links - IE actually navigates to another page while Chrome/FF load the portfolio link in the same page for some reason. For example, clicking on the first project does not navigate away from the homepage in Chrome/FF, it stays on this URL:

http://www.siteurl.com/wordpressdirectory/

Here is how it shows up in IE:

http://www.siteurl.com/wordpressdirectory/?portfolio=project-name-is-inserted-here

Edit: probably should have mentioned I'm using IE8 (8.0.7600.16385), Chrome 24 (24.0.1312.52m) and FF 18 (18.0.1).