Why does CSS3Pie + Prototype 1.6.1 crash Internet Explorer 8

Question

I'm trying to understand why Css3Pie used in conjunction with Prototype 1.6.1 crashes Internet Explorer 8. Why is this happening?

Relevant information

• CSS3Pie [source code] is an Internet Explorer behavior (htc) that adds support for CSS3 properties like border-radius, gradients, etc.
• The crash only happens in IE8, not IE7 or earlier.
• The crash only happens in Prototype 1.6.1 [source code], not Prototype 1.6.0.x
• The crash happens immediately on page load, I'm not even able to interact with the page.
• The developer is aware of the issue but since he believes it is a Prototype issue (it may be), he may not be eager to fix it. There is both a forum post and GitHub bug report, but neither add much information.