Run the following testcase in IE:
<html>
<head>
<script type="text/javascript" src="http://o.aolcdn.com/dojo/1.4.3/dojo/dojo.xd.js"></script>
<script type="text/javascript">
dojo.require("dojox.charting.Chart2D");
dojo.addOnLoad(function(){
var chart = (new dojox.charting.Chart2D("chart")).
addPlot("default").
addAxis("x", {
min: 0,
max: 2
}).
addAxis("y", {
min: 0,
max: 2,
vertical: true
}).
addSeries("Series", [ {x:1,y:1}, {x:1,y:803} ]).
render();
});
</script>
</head>
<body>
<div id="chart" style="width:600px;height:500px;"></div>
</body>
</html>
The chart renders incorrectly as a broken vertical line and no x axis.

Change the series y value from 803 to 802 and it renders correctly. Change it to 809 and the y axis disappears as well. The problems seems to be an IE-specific problem. This was found by my Summer-of-Code mentee (graphing calculator) when plotting lines near vertical asymptotes that go outside the chart boundary as designed. I traced thru plot2d/Default.js and found that when calculating lpoly, that vt() returns a very large number for this testcase, and when subtracted, seems to make IE upset. I hacked up a solution that seems to fix the problem but I'm unsure of what the side-effects will be. I changed:
y: dim.height - offsets.b - vt(v.y)
to
y: Math.max(dim.height - offsets.b - vt(v.y), -178900) IE neg limited
(there were 2 similar occurances of this statement in the same code block).
screenshot