Event registration – captcha doesnt work under IE

Hello, sir!

We are using your Event Registration plugin for WP – here –

http://www.seminaribg.com/2012/12/%D1%81%D0%B5%D0%BC%D0%B8%D0%BD%D0%B0%D1%80-
%D0%BE%D0%B1%D1%89%D0%B5%D1%81%D1%82%D0%B2%D0%B5%D0%BD%D0%B8-
%D0%BF%D0%BE%D1%80%D1%8A%D1%87%D0%BA%D0%B8-2013-19-%D0%B8-20-
%D1%84%D0%B5%D0%B2%D1%80%D1%83/

Click – below , the 3rd button in right

It’s ok, but under IE 8 /and some other versions of IE/ the Captcha doesnt work and we receive a lot of spam?

We need your help to solve this problem, and we can pay for your work.

Also some people doesnt see the Submit button below /under IE again / so they could not send the form info to us.

Thanx in advance.

http://wordpress.org/extend/plugins/event-registration/