I checked demo of your nice extension in all IE, but it didn't work!
it has this javascript error:
Webpage error details
User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; InfoPath.3; AskTbPTV/5.14.1.20007)
Timestamp: Sat, 26 May 2012 21:02:59 UTC
Message: 'console' is undefined
Line: 3522
Char: 13
Code: 0
URI: http://demo.smartaddons.com/extensions/joomla17/content-modules/sj-categories-accordion
check it please..
