paypal button problem on IE

hello In my app I have a PayPal Pay Now button (working on Sandbox mode atm)... it works great on every browser except IE... What is happening? in every browser (FF, Chrome, Opera) when I press on the button it redirects me to the page I want (the page where you pay for the item) but in IE it redirects me to normal login page, not the page in which I have to pay?

anyone knows the reason why is that? This is the last thing I have to complete to mak开发者_高级运维e my app working.

here is my button code:

<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_xclick" />
<input type="hidden" name="business" value="ABCDEFGHXXXX" />
<input type="hidden" name="lc" value="AU"/ >
<input type="hidden" name="item_name" value="Item" />
<input type="hidden" name="amount" value="5.00" />
<input type="hidden" name="currency_code" value="USD" />
<input type="hidden" name="button_subtype" value="services" />
<input type="hidden" name="no_note" value="1" />
<input type="hidden" name="no_shipping" value="1" />
<input type="hidden" name="rm" value="1" />
<input type="hidden" name="return" value="http:/www.domain.com/thanks.php" />
<input type="hidden" name="cancel_return" value="http:/www.domain.com/canceled.php" />
<input type="hidden" name="bn" value="PP-BuyNowBF:btn_paynowCC_LG.gif:NonHosted" /> 
<input type="hidden" name="cbt" value="GO BACK TO XXXXX APP" />
<input type="hidden" name="custom" value="XXXXXXXXXXXXX" />
<input type="image" src="https://www.paypalobjects.com/WEBSCR-640-20110401-1/en_AU/i/btn/btn_paynowCC_LG.gif" border="0" name="submit" style="background-color: #fff;" />
<img alt="" border="0" src="https://www.paypalobjects.com/WEBSCR-640-20110401-1/en_AU/i/scr/pixel.gif" width="1" height="1" />
</form>

Are you sure it's a PayPal account login screen you're seeing? If it says "Please login to use the PayPal Sandbox features." that means you're not logged in as a developer on https://developer.paypal.com/ If you want to use the Sandbox site, in any browser, you need to be logged in to https://developer.paypal.com/ -- that's of course not a restriction you'll see in the live site.
Your code looks fine to me, anyway.