AARP's website is probably not compatible with/up to date for IE9.  Try installing IE9, going to the AARP forum, then clicking on the little "broken page" icon by the Refresh icon and the 'down' arrow.  This will view the page in "compatibility mode" for sites that work with previous versions of IE.
I just downloaded IE 9 on my Windows 7 (64 bit) OS on my laptop. Now, when I try to access a comments thread on AARP, I get this: "The FCKConfig.CoreStyles{'FontFace"} setting was not found. Pleasecheck the fckconfig.js file." I unstalled IE 9 back to IE 8 and the issue didn't occur. I reinstalled IE 9, and it occurred again. And it only occurs on the AARP thread. Does anyone have any idea what is up? I'm totally CONFUSED!....thanks..........:emotion-9:  
After IE 9 Download, AARP Thread Doesn't Work