This is an amazing tool so huge huge kudos for making it as this is a web developers dream!!! However I appreciate its alpha so here to help is a list of websites that cause it to crash...

http://www.msn.com
http://www.readinginfo.co.uk
http://www.miniclip.com
http://www.skynews.com

If you take a look they all feature the same thing on the homepage, flash.

p.s. im using vista sp1 & ie8