Unable to get value of the property 'slice': object is null or undefined

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Added the IE9 code
<!--[if lt IE 9]>
<script 
src="http://ie7-js.googlecode.com/svn/version/2.1(beta4)/IE9.js"></script>
<![endif]-->

2. Put IE9 in IE7 mode

What is the expected output? What do you see instead?
It fails right on start so not seeing any output. I get this error.

Line: 1
Error: Unable to get value of the property 'slice': object is null or undefined


Also it points to this line of code
*element.currentStyle["ie7-height"].slice(0,-1)/100)

What version of the product are you using? On what operating system?
Using 2.1(beta4)/IE9.js

Please provide any additional information below.
Can't even get it to work from the start

Original issue reported on code.google.com by and...@arosolino.com on 26 Feb 2013 at 3:59