EasyCalc Issue

I have received a few calls that tell me they couldn't get past the math captcha because it would say the math was wrong. I have asked them all and this seems to be mainly IE issue. Is there a resolution?

I have no other spam blocks on, I am using a joomla-monster template, not standard. There are no code modifications to core.

I do not use any other form of the captcha as I have had issues with the cache not allowing it to reload for another try.

Thank you for any answer you can provide.