Google +1 button causes JavaScript error

We've recently started using the Google +1 button on our page, but whenever we include the Google sc开发者_StackOverflow社区ript block this JavaScript error comes up in IE8:

"No relay set (used as window.postMessage targetOrigin), cannot send cross-domain message"

This is a weird one, can't find out much about it. Does anyone have any clue what it means? I've tried moving the script include to the top of the page, but it doesn't help.

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Google +1 currently does not work on any version of IE.