XMLHttpRequest And SetRequestHeader In IE Returns An Error

I try to make Cross Domain POST requests and get back JSON encoded responses, everything works fine except in IE 7, 8, 9. I have try those solutions but i get this error: Object d

Solution 1:

Thanks a lot @Esailija who inform me that i can't make set request headers with the XDomainRequest.

So i tried other methods and solutions also and i finally came back with a simpler method:
changed the POST requests to GET and everything working fine after some small changes.