Problem with IE7 and 6

Problem with IE7 and 6

I have a script on my site for a simple animation. It works fine in Safari, Chrome, Firefox, and IE8, but in IE6 and 7 it gives an error and completely messes up my page.

Here is the script:

function slideOff(link,horDist,speed) {
$(link).animate({
'left':'+='+horDist,
'opacity':'0',
},speed)
.animate({
'left':'-='+horDist+'px'
},0)
.animate({
'opacity':'1'
})
}

If you'd like to see the page at a whole it is at joeldrotleff.com. I commented out the script for now, so that my site wouldn't get broken in IE6 and 7, but it's still there to be seen. 

Can anyone explain this? I hope I'm not being a total noob but I can't see anything wrong with the code that would be causing this major problem. 

On a related note: when using fadeOut and fadeIn on my site, the text seems to get bold as it is fading out and fading back in, in all versions of IE. Does anyone know why that might be happening and if there's anything to do about it?

Thanks a lot for any help
Joel