CSS problem in Firefox?

I'm having an issue with the display of my div boxes, and I'm not sure what the problem is. The weird thing is that I've tested using the exact same browser as the client (Firefox v.2.0.0.3), but we are not seeing the same thing, so I can't even try to recreate the problem at my end.

I have several divs stacked on top of each other, with a grey border and two columns of text. It should look something like this:

and it looks fine in both IE and Firefox at my end. However, my client says that, while it looks fine in IE for her, in Firefox, it is looking like this:

She says that the grey lines are not static. They drag around as she scrolls up and down the page. However, they appear to be contained within the div (ex. they are not moving up to the header area or across the page)

Here is my CSS (.services is the container, .servicespic is the left column, and .servicesdesc is the right column):
.services {
width:90%;
padding:10px;
margin-left:30px;
margin-bottom:20px;
border:#CCCCCC solid thin;
overflow:auto;
}

.servicespic {
text-align:center;
vertical-align:middle;
}

.servicesdesc {
width:60%;
float:right;
font:0.9em Tahoma, Arial, Helvetica, sans-serif;
text-align:left;
}

and here is an example of the HTML for the divs:

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