Jquery rounded corners IE error

I've already solved the problem but just listing here as I couldn't google an answer I had to try everything before I found the solution.

I had a site which displayed a list of letters <a href="#" id="a" class="clajaxletter">a</a> ... through the alphabet depending upon if there were entries for the letter. On all pages it worked great in Firefox but in IE on certain pages I had an error in jquery rounded corners and the ajax calls from these letters

The pages were practically equivalent so couldn't figure it out.

I ran the pages through a validator as I assumed something wasn't compliant but this didn't solve anything.

The error on IE was object doesn't support this method jquery.rounded.min.js line 0, It wasn't my site and didn't want to dig into jquery.rounded as I didn't think this was the real problem as rounded corners worked fine on some pages just not certain ones.

So I slowly removed bits of content from a page with errors and finally when removed the ajax link with id="r" the error disappeared (which is why pages without the id="r" on it worked fine

I can only assumed jquery rounded corners uses r in some way to cause IE to puke?

So not quite a question but if you have more insite on this I'll check back.