Form Control Option Button corrupting spreadsheet

Hi

I hope someone can help as this is driving me round the twist.

I am trying to create a questionnaire within excel using Form Control Option Buttons

OptionsBtn.JPG

The buttons for the first question work fine, however if I create any further buttons (for the rest of the questions) I get the following error message

Error Message1.jpg
Error Message2.jpg

If I remove the option buttons the error goes away

Thanks in advance

OK really not sure what the problem was, but I have just upgraded to Office 2013 and it has gone away.