[jQuery] blockUi and Jquery animate function problem (IE7 of course)

[asiarlis]

I use blogUi plug in for a long time know and everything works fine.
Excellent job.

Recently i decide to use the animate function of jQuery to pop up an
absolute position it window that holds form data. The problem is that
when i use the animate function to pop up the window the blockUi in
Internet explorer 7 cannot handle oppacity and cannot display the
loader. Just white background. When the Ajax request finished the
white background removed and the form appears normally.

I try not to use the animate function and the blockUi plugin works
fine in IE7 (and firefox of course). But when i use it i get that
problem.

Any help will be appreciated.

Jquery code:

//Animate form window

$(".sendBtn").click(function(){
        $("#sendToFriendHolder").animate({
        width: "500px",
        height: "210px",
        opacity: 100
      }, 500 );
});


//blockUi code
$('#sendToFriendHolder').block({
          message: '<span class="waitMsg">Please Wait...</span>',
     css: {  border: '1px solid #cccccc',padding: '5px',
width:'80%',cursor: 'wait'}
});